New research suggests that collisions between stars in the early universe were common, which could help explain the rapid growth of supermassive black holes and the existence of strange Little Red Dots seen by the James Webb Space Telescope (JWST).

The team behind this research performed simulations of the early universe and found stellar systems were densely packed, leading to stars frequently slamming into each other. While rapid collisions would have destroyed the stars involved, slower collisions would have led to repeated mergers, creating single over-massive stars, which could collapse and form larger-than-usual black holes at the end of their lives. These could be the seeds of the first supermassive black holes.

Dense stellar environments do still exist in the modern universe at the hearts of galaxies; however, these aren't conducive to the types of collisions that would birth ultra-massive stars. That is because there are already supermassive black holes at the hearts of modern galaxies, and their immense gravitational influence speeds up orbiting stars, meaning collisions that do occur are high-speed and destructive, thus failing to birth overmassive stars.

"Perhaps the strangest outcome of our simulations is that stars can merge repeatedly within the cluster until they form one gigantic star with a mass equal to that of an entire cluster," team member Claire Williams, of the University of California, Los Angeles (UCLA), said in a statement. "When a star this huge reaches the end of its life, models suggest that it may have no option but to collapse into itself and form a massive black hole."

My, haven't you grown? How did supermassive black holes get so big so fast?

The existence of supermassive black holes before the universe was even 1 billion years old is something that has puzzled astronomers since the JWST started spotting them in 2022.

This is because black holes should need at least 1 billion years to complete the feeding and merger processes that result in a "supermassive" status of possessing millions or billions of times the mass of the sun.

One suggestion put forward by scientists to explain this is that supermassive black holes don't start out from scratch. Instead, they form from black hole seeds called intermediate-mass black holes.

Normally, when a massive star collapses, it births a stellar-mass black hole possessing a mass between 10 and 100 times the mass of the sun. This is considerably smaller than supermassive black holes that dominate the hearts of all modern galaxies with masses millions to billions of times the mass of our star.

Intermediate-mass black holes are thought to sit between these two families of cosmic titans with masses between 100 and 100,000 times that of the sun. The problem is, no single star should have enough mass to collapse and create an intermediate-mass black hole. But that is valid only for the conditions we see in the "modern" 13.8-billion-year-old universe in our immediate cosmic vicinity. Conditions were very different further out into the universe and further back in time.

Indeed, such seeds emerged from these new simulations in environments of dense star clustering, which could solve this mystery by allowing those growth processes to get a head start.

"Dense star clusters provide a natural birthplace for massive black-hole seeds in our model," Williams said. "The same environment that forms the black hole can also provide stars and gas that influence its subsequent growth."

However, this could be a two-for-one deal. The JWST has also been routinely discovering astronomical bodies called Little Red Dots in the early universe. Little Red Dots are curious because they seem to have completely disappeared by the time the cosmos reached 2 billion years old.

Little Red Dots the cosmic elephant in the room

Little Red Dots are extremely compact objects in the early universe that get their moniker from the fact that they look like red dots.

"Little Red Dots are a hot topic in astronomy. You can compare studies of people trying to understand Little Red Dots to the tale of blind people who are trying to describe an elephant by touching it, and each person describes it differently based on what part they’re touching," team member and UCLA researcher Smadar Naoz said. "Our research connects several of those perspectives together and may help us see more of the elephant."

There have been many suggestions about the true nature of these objects, but one theory suggests that they possess a rapidly growing black hole at their hearts.

The team's simulations suggest that Little Red Dots may be dense star clusters that are constantly being rocked by repeated stellar collisions. This results in a very large star, which eventually collapses to become an intermediate-mass black hole.

But if that is the case, why were there no Little Red Dots around to celebrate the 2 billionth birthday of the universe?

Less than 1 billion years after the Big Bang, the universe was devoid of well-ordered spiral galaxies, but was instead filled with dense and chaotic clusters of star birth. As these regions were rocked with frequent star collisions, the conditions were right for ultra-massive stars to form and collapse into intermediate-mass black holes.

However, as the universe cooled and expanded, these sites became the building blocks of far less chaotic galaxies. Thus, if Little Red Dots are chaotic star clusters needed to form intermediate-mass black holes, progress toward an equilibrium state could explain why they suddenly disappeared from the universe. The cosmos just wasn't extreme enough to maintain Little Red Dots anymore.

The team's research was published on Monday (Oct. 26) in the Astrophysical Journal.

Something spooky is stirring in the shadows of the infamous star Betelgeuse, a cosmic poltergeist that is disrupting the atmosphere of the red supergiant.

New radio observations have shown Betelgeuse's smaller stellar companion, Siwarha (not Betelguese Betelguese, unfortunately), cutting through the supergiant's extended atmosphere and leaving a wake in its path, like a jet boat slicing through a lake.

Because the name of this red supergiant star located about 650 light-years away from Earth, marking the shoulder of constellation Orion, is Betelgeuse, which means "the hand of al-Jawza" in Arabic, the companion was named Siwarha, meaning "her bracelet."

"This companion is orbiting so close to the star that it actually passes through its extended atmosphere," Lynn Matthews, the principal research scientist at Massachusetts Institute of Technology (MIT) Haystack Observatory who led the new observations, said in a statement.

Astronomers turn cosmic ghost hunters

Using data collected from 2021 to 2026 using the Karl G. Jansky Very Large Array in New Mexico and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, Matthews and colleagues found that Betelgeuse's atmosphere stretches into an egg shape when the companion star is farthest away and rounds out when the companion passes in front of or behind it.

The same data also showed that Betelgeuse itself has largely recovered from the "Great Dimming" that made headlines in 2020. This recovery comes after the red supergiant "sneezed" in 2020, dramatically ejecting tons of gas and dust and fading to its dimmest in more than a century.

Among the long-standing mysteries of Betelgeuse, scientists have puzzled over a brightening and dimming cycle that lasts roughly 2,100 days. Recent studies pointed to a low-mass companion orbiting deep inside the star's atmosphere, and its existence was confirmed in early 2026.

Though Siwarha itself is too faint to detect directly at radio wavelengths, its influence shows up in the star's shape, the new study found. To confirm the effect, the researchers say, they will need to observe more of the companion's orbit, especially at radio frequencies that have so far been sparsely sampled.

The Next Generation Very Large Array, a planned telescope, should make this kind of monitoring far more routine, according to the team. With sharper vision, researchers could see how red supergiants like Betelgeuse shed their material as they near the end of their lives, and how a close companion might affect that process by tugging on that ejected matter.

This research is described in a paper published in The Astronomical Journal.

"Sometimes dead is better." Who can forget the immortal words of Jud Crandall, delivered by the incomparable Fred Gwynne in the 1989 film adaptation of Stephen King's Pet Sematary? Turns out Crandall could have been talking about somewhere just as otherworldly as the cursed Chumash burial ground at the heart of one of King's most terrifying works of fiction.

That's because astronomers have discovered two husks of two zombie planets shuffling through the gory remains of what was once their planetary neighbors around a long-deceased star, or white dwarf. The shattered planets were revealed by a clear gap in the debris around the white dwarf J1328−1450, located around 1,600 light-years away from Earth. One of the remnants is estimated to be no larger than the size of the average solar system asteroid, while the other is estimated to be between the size of the moon and the dwarf planet Pluto.

If this wasn't creepy enough, this haunting planetary system could be a grisly warning about the future of our own solar system after the inevitable death of the sun.

White dwarfs like the one at the heart of this system are formed when stars around the same mass as the sun run out of hydrogen in their cores. This means they can no longer fuse hydrogen into helium, the nuclear fusion process that provides the outward push that supports a star against the inward push of its own gravity.

As a result, the stars' cores collapse while the outer layers, where nuclear fusion is still proceeding, puff out. This so-called red giant phase can see stars increase their radius by many 100s of times. When it happens to the sun in around 5 billion years, our star will expand to consume the inner planets, including Earth.

The red giant phase ends when the outer layers disperse along with the wreckage of consumed planets, leaving a smoldering stellar core, now a white dwarf, surrounded by the disk-shaped remains of its outer layers and cannibalized planetary children. But this may not be the final death of all the planets that once orbited the now-dead star.

"We have known for some time that planets may survive beyond the transformation of their central star, but this is the first example of a complex system with a double debris disc and potentially two surviving planetesimals," research leader Nicola Gentille Fusillo, an astronomer at the Università degli Studi di Trieste, Italy, said in a statement.

Violent stellar death can't kill these two planetary Jason Voorhees

This system differs from others seen because of the large gap between the remarkably stable inner and outer rings. All previously known debris discs around white dwarfs have been surrounded by single, flat, rotating disks, not a double structure like this.

"The system is a rare glimpse of the violent, chaotic process by which a planetary system meets its end, and it hints that dead stars can have disc structures far more complex than previously realized," team member Gentle Fusillo of the Astronomical Observatory of Trieste said.

The team thinks that this unique double structure is evidence of planets that weren't completely vaporized during this white dwarf's red giant phase.

That means just like the residents and campers of Crystal Lake couldn't finish off Pamela Voorhees' baby boy, even an expanding star couldn't finish these two planets.

The team's observations, made with the Very Large Telescope (VLT), revealed the presence of calcium, oxygen, magnesium, and iron in the disk around the white dwarf. This indicates the destroyed planets had a composition similar to the rocky planets of the inner solar system.

The researchers also found evidence of a diversity of composition in the destroyed planets. The chemistry of the outer rings deviated from that of the inner rings, indicating that at least two of the consumed planets had very different compositions.

"The system therefore offers a remarkable glimpse of what the future of planetary systems, including systems like our own, might look like," Lagos-Vilches explained.

The team's research was published on Monday (Oct. 26) in the journal Nature Astronomy.

Scientists are still learning about a cosmic "string of pearls," a unique celestial relic left by a supernova explosion that humanity witnessed around 850 years ago.

That is thanks to the most detailed observation of the dandelion-shaped chains of gas and supernova debris that comprise Pa 30, the only supernova remnant of its type observed in the Milky Way. What makes Pa 30 even more unique is that it has a rare "zombie star" at its heart.

Supernovas like the one that created Pa 30 are called Type Ia supernovas; they happen when a dead star called a white dwarf overfeeds on a companion star like a cosmic vampire. This overfeeding triggers a runaway nuclear explosion that usually destroys the white dwarf. But on rare occasions, the supernova doesn't completely destroy the star, and a shattered stellar body remains, called a zombie star. These events are called Type Iax supernovas.

Pa 30 was first identified in 2013 by a citizen scientist in 2013, but scientists soon linked it to a cosmic explosion recorded independently in the year 1181 in Japanese, Chinese, and Arabic historical documentation. That makes this one of only five supernovas seen before the invention of the telescope.

"Reliable historical records of stellar explosions extend back only about a thousand years. For all we know, there might well be similar remnants still lurking in the dark in our own galaxy," team member Ilaria Caiazzo, assistant professor at the Institute of Science and Technology Austria (ISTA), said in a statement.

"Today, we are lucky to study an intriguing object we know was observed by astronomers who made three independent historical records of the event centuries before the invention of the telescope."

Solar system-sized pearls

Pa 30 is a good laboratory to study supernovas because, at around 7,500 light-years away, it is relatively close to Earth on cosmic scales. For instance, the heart of our galaxy is around 26,000 light-years away. "We can see this much detail because of Pa 30's proximity to Earth," said Caiazzo. "This proximity makes Pa 30 uniquely valuable for study."

It is also an important subject of study because it is the only supernova remnant in which we can see a zombie star.

Using the Gemini North telescope, Caiazzo and colleagues zoomed in on Pa 30, discovering knots along the strands of gas radiating out from the site of the cosmic explosion, like pearls on a string.

These pearls are each wide enough to encompass the orbit of Neptune, the most distant planet from the sun, ten times over.

"The planetary region of our solar system could fit in each knot about ten times with room to spare," said Caiazzo. "The knots are quite strikingly uniform. We are excited to try to model them."

The team also discovered that the zombie star sits almost perfectly at the heart of Pa 30. When these cosmic explosions happen, they should provide any debris, including zombie stars, with a kick. The fact that this "living dead" star still sits dead center of this wreckage suggests that when this explosion happened, it was roughly symmetrical and the kick was relatively light.

"Explosions conserve momentum. If the explosion itself was perfectly symmetric, the ejecta should also be symmetric, and the surviving star should not receive a substantial kick," Caiazzo said. "We were able to measure a precise upper limit of the remnant star's transverse kick speed, showing that it was surprisingly small. We practically don't see the star moving away at all."

While there are still many mysteries surrounding Pa 30 and its zombie occupant, one of the most exciting prospects emerging from this research is the possibility it will help identify the wreckage of other Type Iax supernovas in our galaxy.

"While we can see Type Iax supernovas in distant galaxies as point sources of light, resolving the remnants of such explosions is only possible in our own galaxy and in very few nearby ones," Caiazzo concluded. "Eventually, we plan to use Pa 30's distinctive properties to search the Milky Way and nearby galaxies for similar objects."

The team's research was published in The Astrophysical Journal.

Using NASA’s SPHEREx spacecraft, astronomers have studied a host of "failed stars," also known as brown dwarfs.

These strange cosmic bodies straddle the line between planets and stars, possessing a mass between 13 and 80 times that of Jupiter (0.013 to 0.08 times the mass of the sun). They get the nickname failed stars because they form like stars from collapsing clouds of gas and dust but fail to gather enough mass to trigger the fusion of hydrogen to helium in their cores, the process that powers actual stars.

This formation process also means that brown dwarfs are cosmic loners, wandering the darkness of space alone, bereft of the light of a parent star. That description might sound like lyrics from a Type O Negative song ("Black No. 1," anybody?). And that's apt, according to the leader of the new study, which reveals that, chemically speaking, the atmospheres of these dark and cloudy worlds are not unlike those of our solar system's gas giant planets.

"They’re kind of goth," Zafar Rustamkulov, of the California Institute of Technology (Caltech), said in a statement. "Unlike exoplanets, free-floating brown dwarfs are completely independent celestial objects that will fade into eternity alone. We’re still learning how complex they are."

Rustamkulov added that, from Earth orbit, SPHEREx — short for Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer — sees wavelengths of light that are nigh-impossible to see with telescopes on the ground because water in Earth’s atmosphere absorbs them. That is important for bringing brown dwarfs into the light.

"We are picking up light from the deep, red clouds of brown dwarfs all over the sky," he said.

A forest (of brown dwarfs)

Brown dwarfs have been somewhat mysterious since their discovery in the 1990s, due to the fact that the small amount of nuclear fusion that occurs within them causes them to emit no more than a faint glow. That means that our understanding of their makeup, their storms, and their evolution really only comes from theory.

To help lift this observational darkness, the team turned to data from SPHEREx. They studied 37 nearby brown dwarfs in a spectrum of light including 102 wavelengths, from the deepest red our eyes can see to the invisible infrared light. These local failed stars spanned the full temperature range for brown dwarfs — from 4,000 degrees Fahrenheit to minus 10 degrees Fahrenheit (2,200 to minus 20 degrees Celsius).

Considering that the temperature of the sun is about 10,000 degrees Fahrenheit (5,500 degrees Celsius), you could definitely say brown dwarfs run cold.

The spectra of brown dwarfs seen by SPHEREx allowed the team to determine that their atmospheres are chemically rich in water, carbon dioxide, carbon monoxide and methane.

"We’re seeing the signatures of these molecules and how they change from object to object across the entire temperature regime," said team member J. Davy Kirkpatrick, also of Caltech. "Our paper concentrated on just three dozen, but we have thousands more that we are in the process of analyzing.

"I really want to see what bounds the universe places on the variety of brown dwarfs."

All my colors

Brown dwarfs have been routinely observed by other telescopes, including NASA's James Webb Space Telescope and the agency's now-retired Spitzer Space Telescope, but the wide wavelength coverage of SPHEREx has made it particularly useful in observing these failed stars. That's good news for astronomers waiting for change in the atmospheres of brown dwarfs as they age and grow cold.

The researchers found that some brown dwarfs observed by SPHEREx are at a stage of extreme change in which their clouds are clearing, creating atmospheres rich in methane.

The team may have discovered significant new details about brown dwarfs, but they are still on the proverbial mystery street when it comes to these strange celestial objects,

"The state-of-the-art models are capturing the general chemical trend, but when it comes to these cloudy transitions, the models are struggling to match the data," said Rustamkulov. "No two brown dwarfs are alike. Even at the same temperature, their spectra look quite distinct."

"This journey has turned many of us into accidental meteorologists. We know how hard it is to predict weather on our own planet, and we realize it's going to be just as challenging to explain the phenomena we see in these bizarre, cold objects," Kirkpatrick said. "The findings are a call to action to explore even more of these dark worlds."

As astronomers resond to that call to action, I will ponder how I could have worked Bauhaus' Goth classic "Bela Lugosi is Dead" into this article.

The team's research was published on Sept. 28 in The Astrophysical Journal.

How awesome would it be if the sun could take on a spooky green glow for Halloween? It turns out that scientists have discovered that our star may indeed go green, but only billions of years from now after its death  — and only if it then starts eating planets like a cosmic zombie.

That's possible because scientists have discovered that white dwarfs, the type of stellar remnants sun-sized stars leave behind when they die, can actually take on a range of colors including green if they snack on their rocky planets like cosmic cannibals.

For stellar scientists, the colors of stars have always been indicative of their temperatures. Cool stars look orange, while stars like the sun look white, and the hottest stars glow pale blue. This is akin to a blacksmith's iron glowing red, then orange, then white-hot as it heats up. Researchers have always assumed that white dwarfs follow the same rule. However, new research suggests that these stellar corpses could glow in a range of colors including green, pink, cyan, yellow, and purple. That means the universe is far more colorful than we suspected.

"Most stars, including most white dwarfs, behave like 'perfect radiators,' so their color is set almost entirely by temperature. But nobody had really looked into what else might be possible for white dwarfs," team leader Mark Hollands of the University of Warwick said in a statement sent to Space.com.

"It turns out these incredibly dense stars caaaaan produce colors nobody expected, and some of them genuinely surprised me."

How white dwarfs break stellar color rules

White dwarfs get their name because when they were discovered, they appeared surprisingly hot and glowed white or pale blue. However, this new research suggests that this slightly bland and uniform appearance is because no white dwarf is close enough for Earthbound astronomers to see their true colors.

The key to the rainbow-like array of colors this team suggests white dwarfs could possess is their density. White dwarfs form when stars with a mass roughly that of the sun run out of fuel and can no longer support themselves against their own gravity, causing their cores to collapse. As a result, the matter that makes up white dwarfs is around the density of water, millions of times denser than the sun's surface, the photosphere.

In these conditions, elements like carbon, calcium, and sodium can interact with the surrounding dense helium plasma and absorb light across a wider range of colors than they would at lower densities. That shifts the colors of white dwarfs away from the white/light blue seen for a perfect radiator of heat.

The researchers found that the colors of white dwarfs would fit into distinct groups tied to the individual chemical makeup of the stellar remnant's atmosphere.

White dwarfs abundant in carbon should be pink or purple, while those that have been enriched with debris from consumed asteroids and comets, and the remains of old planetary systems, would take a more yellow hue. Cooler white dwarfs with mixed hydrogen and helium atmospheres often would glow cyan or pale blue, caused as hydrogen molecules collide with helium atoms in their dense atmospheres.

One of the most striking examples of white dwarf coloration, however, would arise when one of these living dead stars starts feeding on the planets around it like a horror movie zombie.

Zombie white dwarfs go green

The researchers found that some dead star white dwarfs can go a little green around the gills after snacking on orbiting planets.

An example of this is WD J1330+6435, a cool white dwarf located around 326 light-years away, which has been accreting rocky material from a planetary companion. This has enriched its atmosphere with calcium, lithium, and sodium, and the team's model suggests this would have led WD J1330+6435 to adopt a green hue.

But unlike the green-tinged zombies of George Romero's classic Dawn of the Dead, there are no hordes of these green-faced cosmic zombies ... yet.

The researchers think that no other star, living or dead, has ever been credibly reported as green. That makes WD J1330+6435 the first known genuinely green star.

"The traces of sodium in the atmosphere of this white dwarf absorb the orange part of the spectrum, leaving behind a ghostly green glow," Hollands said. "Imagine standing on a planet and looking up at a green star. It feels like something out of science fiction."

Scientists see red

The team didn't just discover that a known white dwarf is the first-ever green star; they also discovered what could be the reddest star ever in the form of the white dwarf WD J1011+2845.

Located just 48 light-years from Earth, this white dwarf has a deep convection zone that carries carbon from its core to its surface. These carbon molecules distort light from the white dwarf, causing a deep salmon-pink glow unlike anything seen in any other star.

Despite this rainbow of white dwarfs, the team theorizes that white is still the most common color for these stellar corpses. Only five of the 151 white dwarfs within around 65 light-years of Earth have extraordinary coloring. Extrapolating this to the total population of white dwarfs, the team estimates that only one in 30 of these dead stars has an unusual color.

"One in thirty might not sound like a huge fraction, but across the entire population of white dwarfs in the universe, that is still a lot of oddly colored stars out there," Boris Gänsicke, Department of Physics, University of Warwick, said. "Yet if we take the median across a representative population of white dwarfs, we found that the average white dwarf really is white."

The team's research was published on Thursday (Oct. 14) in the journal RAS Techniques and Instruments.

A new image from the European Space Agency's Mars Express spacecraft reveals the powerful erosive forces that have shaped and re-shaped the surface of the Red Planet over long periods of geological time.

What is it?

This new Mars Express image captures Amazonis Mensa, a large, flat mountain on the Red Planet that offers planetary scientists a glimpse into the many factors that can sculpt a world's surface.

In this photograph, several features stand out to help illustrate this. Easiest to make out are the large round craters created by ancient impacts on the surface of Mars. However, many of these craters have been at least partially filled by lava flowing across the surface of the Red Planet around three billion years ago, according a statement from the European Space Agency (ESA) accompanying the image.

More interestingly, rippled structures known as yardangs can be seen to the left and right sides of the image. These ridges "form as loose sand particles are whipped up by wind and deployed a little like a cosmic sandblaster," according to ESA.

In the image, the two groups of yardangs ripple across the Martian surface in two different directions. This is because Amazonis Mensa acts as a windbreak, pushing material blown by winds in separate orientations.

Why is it incredible?

For over 20 years, Mars Express has been providing scientists with an unparalleled look at the Martian surface, helping us better understand the forces that have shaped the Red Planet over eons.

Now you see them, now you don't. Scientists have discovered that some of the universe's most powerful explosions, hypernovas, may not happen at all.

These explosions, known as hypernovas, were first proposed to explain unusual stars in the halo of our galaxy, the Milky Way, and in a neighboring dwarf galaxy. It was suggested that these stars could only form from the debris of an explosion 10 times more powerful than the 'average' supernovas.

The team behind these new findings suggests that ordinary supernovas could actually account for these stars when the uneven or non-spherical way they fling out matter is considered.

"If we look at a supernova today, the star's materials are not spread evenly. Oxygen might predominantly fly in one direction, sulphur in another. New stars might form from a mix of pieces of the supernova, not its overall mix of elements," team leader Anmol Aggarwal of University College London (UCL) said in a statement. "We developed mathematical models that took account of this and found in all cases that stars with a very unusual mix of ingredients were most likely formed from ordinary supernovas.

"All the evidence we see for hypernovae is suddenly gone."

Hypernova vs. supernova: What's the difference?

Supernovas occur when massive stars run out of fuel for nuclear fusion, effectively ending their lives. This results in the star's core collapsing, sending shockwaves rippling through its outer layers, causing explosions we call supernovas.

Hypernovas are proposed to occur in a similar way, but for an even more massive and rapidly spinning star. This results in a vastly more energetic explosion.

When supernovas or hypernovas happen, they fling elements that the dying star has forged throughout its lifetime into their surrounding cosmic environments. These elements eventually become the building blocks of the next generation of stars.

That means analyzing the chemical signatures of stars can tell stellar scientists about their family histories.

"Just before a star goes supernova, it has layers like an onion, with heavier elements at the center and lighter ones further out. Our model looks at how much material from each layer or each region would be needed to fit the observed star," Ralph Schoenrich of Mullard Space Science Laboratory at UCL said. "We still don’t know how well the supernova material gets mixed before it forms new stars. That is despite decades of work in this area. Our research suggests some mixing goes on, but incomplete mixing.

"We need to take this into account in our models of how chemicals evolve in galaxies and of how the interstellar medium works."

The team began their investigation by observing four stars that are suspected to have been forged from material ejected in a hypernova explosion. Three of those stars were more likely to have been created after supernovas, the team concluded.

The scientists then studied a single red giant star in the halo of the Milky Way with an odd chemical composition, including an overabundance of heavy elements like silver and uranium. These are too heavy to be forged in the cores of all but the most massive stars, the kind of stars that go hypernova.

Such elements could also be created when two massive and dense stellar remnants called neutron stars collide and merge. However, this star doesn't have certain other heavy elements that would be present after a neutron star collision.

This team considered the origins of this star using a model of the Milky Way that has been rapidly enriched with elements heavier than hydrogen and helium, which astronomers call metals, via the death of the first generation of stars.

The rapid speed at which the star spins and the fact it exists at the outskirts of the Milky Way led the team to conclude that this star escaped a metal-poor dwarf galaxy and was eventually dragged into our galaxy. The event that created it, they concluded, was the combination of a neutron star merger and an ordinary supernova.

No hypernova required. An asymmetrical supernova would be enough, the scientists found.

The team's research was published as two papers in the journal Monthly Notices of the Royal Astronomical Society.

Astronomers investigating mysterious flashes of X-rays believe that these blasts could stem from collisions between neutron stars, the events that forge elements like gold, silver, and platinum.

The event designated EP250704a, was first seen on July 4, 2025, as a blast of gamma rays lasting half a second followed by a bright X-ray emission lasting 10 minutes. After receiving an alert from the joint European-Chinese Einstein probe that witnessed the blast, a team of astronomers started to hunt for its cause by studying the aftermath of the explosion using the European Southern Observatory's Very Large Telescope (VLT), the Very Large Array (VLA), and other telescopes.

According to astronomer Niccolò Passaleva who led the observations of the X-ray flash with the VLT, this cosmic outburst was unlike any scientists had seen before. "This is the longest-lasting prompt X-ray flash ever observed from a neutron star merger," Passaleva said in a statement. "It is an opportunity to have a front-row seat to the most extreme forces of the universe and discover more of its secrets."

Neutron stars are created when massive stars die in supernova explosions, cramming one or two the mass of the sun into a width akin to a city on Earth and creating material so dense that a single teaspoon of neutron star matter brought to Earth would weigh 10 million tons. When these extreme dead stars slam together, they create environments so turbulent and violent they are capable of forging elements so heavy that even the hearts of stars can't do it. Elements like the gold on your finger.

These collision and merger events, marked by flashes of light called kilonovas, have long been associated with flashes of high-energy gamma-rays that disappear within two seconds, but new research suggests some neutron star mergers could reveal themselves via blasts of X-rays lasting minutes.

In particular, scientists have wondered if neutron star mergers could be the cause of hundreds of X-ray flashes in distant galaxies discovered by the Einstein probe since its launch in 2024. While some of these have been linked to the supernova-explosive death of massive stars that can create a neutron star or a black hole, others have defied explanation. EP250704a is one such X-ray flash.

"When I saw the X-ray data from this new event, I realized something was up," team member Eleonora Troja, part of the Einstein Probe European collaboration, said in the statement.

The team believes that there is something special in the neutron star merger mix that results in these X-ray bursts.

Merging with a magnetar

All neutron stars are created the same way from the collapsing core of a massive star, but not all neutron stars are equal.

Just as an ice skater pulls in their arms to increase the speed of a spin, the rapid reduction in radius of a collapsing stellar core can "spin up" the rotation of a neutron star to 'over 700 times per second. This collapse can have another consequence too.

It turns out that magnetic fields get stronger when magnetic field lines are pushed closer together. That means the collapse of a stellar core with an already powerful magnetic field can create a neutron star with the strongest magnetic field in the universe. Those neutron stars have a special name: magnetars.

The team behind this research thinks that the neutron star merger in question involved at least one magnetar.

"If the remnant of the collision is a magnetar, it could keep bursting for longer," Troja said. "Magnetars are rapidly spinning neutron stars with huge magnetic fields. When they dump their magnetic power into the surroundings, they can make any explosion brighter and longer-lasting."

The researchers ruled out a supernova as the cause of the X-ray burst and were also able to determine that the light from this collision has been travelling to Earth for 6 billion years.

Discovering more of these extreme X-ray flashes could help astronomers determine how often magnetars are formed through these neutron star mergers, Passaleva said in the statement.

The team's research was published in the journal Science Bulletin.

Astronomers have observed a "vampire" star feeding on a brown dwarf companion for the first time. It is a slow and gruesome death that could last for billions of years, despite the fact that the star is snacking on the equivalent of 5.2 trillion quarter-pounder burgers every second.

Brown dwarfs straddle the line between planets and stars, with masses from 13 to 80 times that of Jupiter or 0.013 to 0.08 times that of the sun. They get their unfortunate nickname "failed stars" because, though they form from a collapsing cloud of dense gas, they fail to gather enough mass to trigger the nuclear fusion of hydrogen to helium in their cores, the process that defines what a star is.

This newly discovered brown dwarf, found to be a snack for a small companion star, is located in the system ZTF J0440+2325, which dwells around 300 light-years from Earth. This represents the first time astronomers have seen a low-mass star acting as a stellar vampire, stealing material from a low-mass stellar companion. The slow rate at which this is occurring indicates this cosmic vampirism will last for hundreds of thousands to billions of years.

"When we think of stars interacting with planets or brown dwarfs, the picture is always that the star eventually swallows the other thing," team member Kevin Burdge of the Massachusetts Institute of Technology (MIT) said in a statement. "This is what will happen to the Earth when the sun becomes a red giant. But here, we've found an alternative: Instead of swallowing the thing up, the star can gradually eat it for billions of years."

A strange cosmic triangle

This new system was first observed in observations of the sky conducted by the Zwicky Transient Facility (ZTF) in the form of a strange light triangle that repeatedly appeared in the data.

"I remember first looking at this and thinking: Stars don't make triangular waveforms like this," Burdge explained.

At the time, Burdge and colleagues were hunting for so-called "black widow pulsars" that contain a stellar remnant called a neutron star feasting on a companion star much like how the arachnid of the same name devours its prey. However, because these systems contain a low-mass object gravitationally tugging on a high-mass companion, there is usually a "wobble" in their light signature, and the team found no "wobble" in this particular light signature.

"We weren't seeing that whipping back and forth here," said Burdge. "It didn't make any sense. We couldn't explain what this was."

Ruling out a black widow pulsar as the origin of this strange repeating light signal in ZTF data, Burdge and colleagues followed another hunch; proposing that this is a more balanced system with objects of similar masses.

"If you have less mass in the system overall, things can gently orbit each other without whipping back and forth," Burdge said. "That was the idea. But we never had any proof. And this weird triangle just sat for years."

That was until Burdge and colleagues revisited it, determining it originated from within the boundary of the Milky Way. Designating the source ZTF J0440+2325, the team followed up with multiple telescopes. With further observations, they found a slight wobble, less than seen for black widow pulsars but not insignificant.

"That was the real clincher for this system," team member Aaron Householder of MIT said. "When we measured that wobble, we found we were not seeing a black widow. This was a low-mass star that’s orbited by a brown dwarf. The wobble was too small in amplitude to be anything else."

What else do we know about ZTF J0440+2325

The researchers were able to figure out that the brown dwarf takes around 87 minutes to orbit the star feeding upon it. That means that this entire system could fit within the sun.

The team was also able to determine the mass of both bodies in ZTF J0440+2325. The star has a mass around 85 times the mass of Jupiter, with the brown dwarf has a mass around 25 times the mass of the gas giant.

Though the star is stripping and accreting matter like black holes sometimes do with stars, the huge difference in size between the star in ZTF J0440+2325 and a typical black hole means this proceeds differently. That is because, despite having many times more mass than the sun, black holes are smaller than the sun with radii ranging from 6 miles to 190 miles (9 kilometers to 300 kilometers).

When a black hole strips matter from a star, this stolen material forms an accretion disk around the black hole that then gradually feeds it. In the case of this system, the stolen brown dwarf matter is falling directly to the star.

"The difference here is: The thing absorbing matter is not a tiny black hole but a star, which is relatively big in size," Burdge said. "So matter just pummels directly onto the surface, at very high speeds, like an asteroid hitting the moon."

The team estimated the rate at which matter falls from the brown dwarf to the star, finding it to be the equivalent of 1/100,000 of Earth's mass per year. That's about 5.2 billion quarter-pounder burgers every second, or maybe 1.2 trillion 1-pound burritos if burgers aren't your speed.

That seems like a lot, but it is just a tiny fraction of the brown dwarf's total mass, making this a slow and steady transfer of material that could go on for billions of years.

This neatly loops back to the initial puzzle that began the investigation into this system in the first place: that weird triangle light signature. Viewed from a distance, the steady feeding process would proceed like a triangle as the victim brown dwarf orbits the star that is eating it.

"It's like you've got this continuous fireball on one of the objects, and as one orbits the other, that hotspot comes in and out of view, and the peak of the triangle signal is when you’re looking right at the fireball," Burdge said.

The team now intends to hunt for more similar systems within the Milky Way.

"It's inspiring a lot of new searches on our part,” Householder concluded. "I think we're going to learn a lot about a different kind of way that planets and brown dwarfs interact with their host stars."

The team's findings were published on Monday (Oct. 5) in the journal Nature Astronomy.

Astronomers have caught a white dwarf, the type of stellar remnant the sun will leave when it dies, in a rare stage of its evolution. The white dwarf orbits a "cosmic lighthouse" in the form of a neutron star spinning hundreds of times a second sweeping twin beams of radiation across the universe, a so-called millisecond pulsar.

The binary system, designated NGC 362D, serves as a rare laboratory to study what happens after a star has spent millions of years donating stellar material to a neutron star before it "dies" to birth a white dwarf. NGC 362D was discovered recently using the MeerKAT radio telescope in South Africa, with the white dwarf companion found in archival data from the Hubble Space Telescope collected between 2006 and 2016. This data also helped to reconstruct the evolutionary history of this system.

This revealed that the white dwarf in this binary system is the youngest white dwarf ever seen to be partnered with a millisecond pulsar. Additionally, this stellar ember also seems to be emitting less ultraviolet radiation than it should. This indicates that when the white dwarf stopped transferring matter to its neutron star companion around 600 million years ago, it was left in an envelope of ejected material that is now blocking UV radiation.

"What makes this system particularly interesting is the possibility of observing it at a very early stage of its evolution," team leader Greta Ettorre of the University of Bologna, Italy, said in a statement sent to Space.com. "Moreover, the attenuation of the signal that we observed in the ultraviolet could indicate the presence of material still surrounding the white dwarf."

A tale of two dead stars

The young white dwarf isn't the only dead star in this system. Like all neutron stars, the pulsar component of NGC 362D was born when a star with between eight and 12 times the mass of the sun died in a massive supernova explosion.

This sees the star's core, with a mass between one and two times that of the sun, crush down to a width of around 12 miles (20 kilometers). The resulting neutron star is therefore composed of matter so dense that if a teaspoon of it were scooped out and brought to Earth, it would weigh around 10 million tons. That is the equivalent of stacking 85,000 adult blue whales on a spoon.

There is another extreme consequence of this rapid stellar core shrinkage. Think of an ice skater here on Earth drawing in their arms to increase their rate of spin, which happens due to the conservation of angular momentum. The same happens with a newborn neutron star but on a much grander scale; some pulsars have been measured to spin in excess of 700 times per second.

This speed can be boosted in systems like NGC 362D, in which a neutron star is snatching material from a donor star because that material carries with it angular momentum. This is referred to as "pulsar recycling."

The theft of this material results in the companion star losing its outer layers, pushing it toward transforming into a white dwarf. This seems to have happened relatively recently for the white dwarf in NGC 362D.

"NGC 362D currently offers us a unique opportunity to study what happens in the immediate aftermath of the millisecond pulsar recycling process," team member and National Institute for Astrophysics (INAF) researcher Emanuele Dalessandro said. "In this context, the possible presence of material around the white dwarf is particularly interesting.

"In fact, it could produce signatures at radio wavelengths in addition to the optical, similar to those observed in systems with non-degenerate companions, and could therefore help us correctly interpret the properties of other young systems."

That means that the team's findings could be of great value in the understanding of other similar systems, especially those at these rare evolutionary stages. The results could also be of use in the continuing effort to use populations of pulsars as "cosmic clocks" in so-called "pulsar timing arrays."

"Millisecond pulsars rotate with extraordinary regularity and can be used as true natural clocks. Measuring the arrival times of their pulses with extreme precision allows us, among other things, to study gravity under extreme conditions and to carry out increasingly precise tests of general relativity," Ettorre concluded. "Understanding their surroundings and reconstructing their evolutionary history is therefore essential to fully exploit what these remarkable cosmic laboratories can tell us."

The findings were published on Wednesday (Sept. 30) in the journal Astronomy & Astrophysics Letters.

Using the X-ray spacecraft XRISM (X-ray Imaging and Spectroscopy Mission), astronomers have observed stellar winds from a hypergiant star feeding an extreme stellar remnant known as a neutron star, left over after a massive star dies.

Neutron stars are considered so extreme because the process that creates them crams between one and two times the mass of the sun down into a sphere with a width of around 12 miles (20 kilometers). This means that the matter that comprises neutron stars is so dense that if a teaspoon of it were brought to Earth, it would weigh as much as 10 million tons, or about the same as 85,000 adult blue whales. In addition to this some young neutron stars, known as pulsars, spin as rapidly as 700 times per second while also blasting twin beams of radiation that sweep across the cosmos like beams of light from a cosmic lighthouse.

Using XRISM and focusing on the system BP Crucis, located about 13,000 light-years away, astronomers investigated what happens when stellar winds from a blue hypergiant star dump ionized gas or plasma on the surface of a pulsar called GX 301-2. The star in question is Wray 977, which has around 40 times the sun's mass and 60 times its size. This means Wray 977 is so hot that it constantly emits a stream of plasma.

GX 301-2 rotates once every 11 minutes and takes around 42 Earth days to orbit its blue hypergiant stellar companion. The team theorizes that the immense gravity of the neutron star creates a dense stream of plasma that it passes through during its orbit, causing flares of X-rays. These flares are more extreme when the neutron star is closest to its stellar donor and thus passing through a denser stream of plasma.

"We've never before seen clear indications of wind plasma falling onto a compact object," team leader Roi Rahin of the University of Maryland, Baltimore County and NASA Goddard Space Flight Center said.

XRISM honed in on BP Crucis using its Resolve instrument in February 2025 for around 16 hours, catching the tail end of one of these extreme flaring events.

From these observations, the team discovered the speed and direction of the plasma stream bombarding GX 301-2. They found the plasma stream is travelling at 335,000 miles per hour (540,000 kilometers per hour), around 200 times faster than the top speed of a Lockheed Martin F-16 jet fighter here on Earth.

"It was clear that these observations were groundbreaking, but at the same time this meant the analysis had to be especially detailed," Nazma Islam, a researcher at the Manipal Center for Natural Sciences, India, said in a statement. "We could see how the dense stream of plasma acts very close to the neutron star."

What's going on around this extreme dead star?

The team theorizes that as the neutron star enters the stellar stream, it sweeps plasma toward itself, creating a thick disk of matter around the stellar remnant. The gas is fed from the disk to the neutron star, causing it to heat up and emit X-rays.

The disk fragments as the neutron star passes further into the densest region of the river of plasma. That is because the matter at this point no longer has enough angular momentum to maintain the disk.

With the disk gone, though it briefly reappears, albeit spinning in the opposite direction, the plasma can directly hit the neutron star's surface, the process that creates the most intense X-ray flaring. The neutron star moves completely through the stream over a period of four Earth days.

"The BP Crucis system is an ideal laboratory for studying wind-fed pulsar accretion, and XRISM's sensitive, high-resolution Resolve spectrometer is an ideal instrument for advancing our understanding of the processes involved," said Brian Williams, the mission's project scientist at NASA's Goddard Space Flight Center.

The team's research was published on Friday (Sept. 18) in the journal Science Advances.

The way in which the ghostly particles known as neutrinos can switch from one kind to another might help explain which stars explode and which collapse to form black holes, a new study finds.

These new findings might also help explain a number of other cosmic mysteries, such as why astronomers have detected fewer supernovas than expected.

When a massive star finally depletes its store of fuel, without nuclear reactions driving the star to expand, its core will implode under its own weight. The extraordinarily high heat and pressure resulting from this collapse will crush protons and electrons together, forming neutrons. This in turn releases a flood of ghostly particles known as neutrinos.

Generally, neutrinos barely interact with all forms of matter. However, when a massive star's heart collapses, it releases a staggering amount of neutrinos — enough for many to slam into and heat the layers just outside the star's core. In some cases, such neutrino heating can lead the rest of the star to explode as a supernova, and leave behind an extraordinarily dense cluster of neutrons known as a neutron star. In other cases, neutrino heating fails to lead to an explosion, and the star collapses, forming a black hole.

"Neutrinos are not a side detail in supernovas," study co-author Mariam Gogilashvili, a particle astrophysicist at the University of Copenhagen's Niels Bohr Institute in Denmark, told Space.com. "They carry away about 99% of the energy released when the core collapses, and a small change in how they behave can decide the fate of the whole star."

Much remains uncertain about which massive stars explode to birth neutron stars and which collapse to form black holes. Uncovering these details could help shed light on a wide range of activity in the cosmos, like the way in which dying stars filled the universe with the kind of matter that nowadays makes up everything from planets to people.

To yield insights on these mysteries, scientists investigated the role the strange nature of neutrinos might play. There are three "flavors" of neutrino — electron, muon and tau — which are named after the kind of particle each flavor generates if they ever collide with matter. In 1998, physicists discovered that neutrinos can "oscillate," or change from one flavor to another, a finding that won the 2015 Nobel Prize in Physics. (There are three corresponding flavors of antineutrino that can similarly change flavor.)

Both muon and tau neutrinos (and antineutrinos) are much less likely to interact with regular matter than electron neutrinos (and antineutrinos). This suggests neutrino flavor change might potentially influence how much neutrinos can heat up matter in a dying star and trigger an explosion.

Previously, scientists thought flavor change would only play a negligible role in the way dying stars collapsed. However, over the past decade, physicists have found that given the astoundingly large number of neutrinos that dying stars generate, many neutrinos are concentrated enough to interact with each other, triggering flavor changes within the core of the collapsing star.

In the new study, the researchers simulated the collapse of 195 stars, ranging in size from nine to 120 solar masses. They analyzed different assumptions about where neutrino flavor conversion occurs in the cores of collapsing stars.

The scientists found that neutrino flavor change might make dying massive stars significantly less likely to explode as supernovas and form neutron stars, and more likely to collapse to create black holes.

"What surprised us most was that the stars between 16 and 30 times the mass of the sun, many of which explode comfortably in our standard simulations, turned out to be particularly sensitive to neutrino physics," study co-author Irene Tamborra, a particle astrophysicist at the University of Copenhagen's Niels Bohr Institute in Denmark, told Space.com "A large number of them fail once flavor conversion is included."

These new findings might help solve a number of longstanding mysteries. For instance, astronomers have detected fewer supernovas than theoretical predictions — neutrino flavor change might help explain these findings, Gogilashvili said. Neutrino flavor change might also help reveal why the biggest red supergiant stars appear to vanish without generating supernova explosions — they may collapse as black holes.

Moreover, the scientists estimated that neutrino flavor change might yield less massive neutron stars. This could help explain why astronomers have detected neutron stars with lower masses than previously theoretically predicted, Tamborra said.

In the future, the scientists want to include more realistic models of neutrino behavior in 3-D computer simulations of massive stars, so neutrino flavor change starts and evolves over time as the stars die.

Gogilashvili and Tamborra detailed their findings in September in the journal Physical Review D.

One of the most rapidly changing stars ever seen, the "born-again" star called Sakurai's Object has entered a new stage of its evolution. This stage involves the star shedding material in a powerful stellar wind while heating up and extending over a region similar in size to our solar system.

The star, also known as V4334 Sagittarii, is located around 10,000 light-years away and became an object of intense fascination for astronomers in 1996 when it sprang back to life after earlier entering the final stages of its evolution.

Most stars evolve over millions or even billions of years, timescales far longer than a human lifetime. That means astronomers usually have to build a picture of stellar evolution from snapshots of different stars at different stages of their lives. By occurring in a figurative blink of a cosmic eye, the evolution of Sakurai's Object offers scientists a rare opportunity to investigate the stellar life cycle.

"Sakurai's Object offers something far rarer. It is one of the very few stars known to have changed dramatically within just a few decades, giving us the opportunity to watch stellar evolution unfold in real time," Albert Zijlstra from Jodrell Bank Centre for Astrophysics at The University of Manchester said in a statement. "With our observations, we can test theories of how stars evolve and gain new insights into one of the shortest and least understood phases in the life of a dying star."

The pathology of a dying star

Sakurai's Object was once like the sun, but it long ago exhausted its fuel needed for nuclear fusion, meaning it was on its way to collapsing to become a white dwarf stellar remnant. That is the kind of dense stellar corpse the sun will leave behind when it dies in around 4.6 billion years.

That was until Sakurai's Object underwent a rare event called a very late thermal pulse, which occurs when a layer of helium inside a star reignites suddenly. This reignition causes the star to rapidly expand and cool while also ejecting vast amounts of stellar material into space. This results in the star effectively returning to an earlier stage in its evolution, giving it a second chance at life, hence the "born again" tag.

Scientists have only witnessed this very late thermal pulse process occurring in two stars, Sakurai's Object and V605 Aquilae. However, the fact that Sakurai's Object ejected vast amounts of material as it sprang back to life means that it is surrounded by a vast envelope of gas and dust, making it difficult to study.

To perform their study, this team turned to the Very Large Telescope (VLT), making observations of Sakurai's Object that could then be compared to stellar evolution models simulating the atmospheres and powerful winds of Wolf-Rayet stars.

This investigation revealed that Sakurai's object has a temperature between 48,000 and 35,700 degrees Fahrenheit (27,000 and 36,000 degrees Celsius). This means the born again star is now reheating after its expansive resurrection seen in 1996, but not quite how scientists expected.

"One of the key questions is how quickly Sakurai's Object should recover after its dramatic eruption. Our measurements show that the star is reheating more gradually than some earlier models predicted," Zijlstra said. "That gives us an important way of testing which theories best describe what happens when a dying star briefly springs back to life."

The team's findings indicate Sakurai's Object is at an earlier stage of its evolution than V605 Aquilae, which underwent its own very late thermal pulse episode around 80 years ago.

The team will now continue to observe Sakurai's Object as it continues its journey toward becoming a white dwarf.

"As we continue to monitor the star over the coming years, we expect to learn much more about this remarkable phase of stellar evolution," Zijlstra added.

The team's research was published on Wednesday (Sept. 16) in the journal Monthly Notices of the Royal Astronomical Society.

When stars the size of our sun die, they leave behind powerful stellar remnants called white dwarfs — and these white dwarfs can transform into even more extreme objects called neutron stars, composed of the densest material in the universe. However, scientists have found that conditions must be "just right" for the major makeover to occur. You can think of it like a cosmic "Goldilocks" situation.

As it turns out, the white dwarf has to be feeding on a companion star like some kind of cosmic vampire.

Neutron stars and white dwarfs are both born when stars run out of the fuel supplies needed for nuclear fusion happening in their cores, but the difference between the two lies with their masses.

Stars with masses similar to that of the sun end their lives when they run out of hydrogen in their cores. This halts the nuclear fusion process — which involves converting that hydrogen to helium — leading to the stars collapsing and shedding their outer layers to become a white dwarf with around the mass of the sun crammed into the width of Earth.

When stars with masses around eight times that of the sun collapse after running out of hydrogen in their cores, they generate enough pressure and heat in these cores to fuse the produced helium into even heavier elements. This process only ends when the star attains a core of iron. The final collapse results in a supernova explosion and creates a neutron star with a mass between one and two times that of the sun. That's the usual way neutron stars form.

However, what if there's a bridge between the white dwarf scenario and neutron star scenario? Scientists have long suspected there is indeed a pathway for a white dwarf to become a neutron star. This new work maps out that pathway, calling it accretion-induced collapse (AIC).

"In AIC, the progenitor is already a stellar remnant, and the trigger is not its own evolution but material handed to it by a companion," team leader Laurenz Thümmler of ETH Zurich told Space.com.

The researcher added that an AIC begins with a stellar remnant in the form of a white dwarf, while the traditional route to birthing a neutron star begins with a massive "living" star. Yet, in the AIC, the collapse of an overfeeding white dwarf continues in a broadly similar way to the collapse of a massive star that creates a neutron star.

As Thümmler explains, in both cases, the neutron star creation process involves the massive star's core imploding and zippy particles called "neutrinos" carrying away energy from the event. However, an important difference is in the "standard" massive star collapse scenario, the subsequent core-collapse supernova and neutron star birth happens inside a thick envelope of material that has been ejected during the massive star's death throes. In AICs, however, this thick envelope of matter is absent.

"AIC is expected to be faint and fast, and why so little matter is ejected compared with an ordinary supernova. Not all white dwarfs could undergo an AIC, and that is the essential point."

Though AICs have been theorized about for years, Thümmler and team wanted to know what characteristics a white dwarf would need in order to undergo this transformation. They set about investigating this using 3-dimesional simulations.

It's what is inside that counts

Most white dwarfs consist of carbon and oxygen. However, some stars collapse to form a white dwarf composed of oxygen, neon and magnesium. That only happens for a narrow range of stellar masses, meaning this composition represents a minority population of white dwarfs.

When carbon and oxygen white dwarfs overfeed on stellar material from a companion or donor star, they eventually reach the so-called Chandrasekhar limit, usually around 1.4 stellar masses. Above this limit, they can go supernova. They don't become neutron stars as a result of these "Type 1a" supernovas, however, but are rather completely destroyed. Oxygen, neon and magnesium white dwarfs can avoid that destruction thanks to their high densities.

"They are typically born more massive and denser than carbon-oxygen white dwarfs and therefore require less additional mass to approach the Chandrasekhar limit," Thümmler said.

However, Thümmler and colleagues discovered this isn't the only condition needed to provoke an AIC. The white dwarf can't be too greedy either.

The team found that the accretion rate, or rate at which material from the donor star falls onto the white dwarf, has to fall within a fairly narrow window to allow an AIC to occur.

"If it is too low, nova eruptions can expel much of the accumulated material again; if it is too high, winds, envelope expansion, or binary interaction can prevent the white dwarf from reaching the conditions required for collapse," Thümmler said. "The accretion has to be fast enough, and steady enough, to get it there without triggering explosive burning along the way.

"When those conditions hold, electrons are captured onto neon and magnesium nuclei. This removes the pressure supporting the star, and the collapse follows."

All this means that AICs are expected to be rare events, although the rate at which they occur remains highly uncertain.

The team also found the environment around AICs is somewhat surprising.

"We expected the most neutron-rich material, which produces the heaviest elements, to emerge along the rotation axis, since that is where the magnetically driven outflow is strongest," Thümmler said. "It does not."

Instead, the team's models revealed neutron-rich material emerging at the mid-latitudes of white dwarfs as they transform into neutron stars. This is region where the outflows of matter driven by intense magnetic fields collide with winds heated by energy-carrying neutrinos.

Thümmler explained that this is significant because it means that these events would appear different based upon the angle at which they are observed.

How to spot white dwarf transformations

Laurenz said these AICs could be identified by Vera C. Rubin Observatory and other telescopes as a bright ultraviolet and optical event lasting two to three days, potentially accompanied by X-ray emissions and longer-lasting radio emissions.

However, the neutron stars created by such events may be difficult to distinguish from stellar remnants birthed in the traditional way.

"They are expected to populate the lower end of the neutron-star mass distribution because the collapsing white dwarf has a mass close to the Chandrasekhar limit and ejects relatively little material," Thümmler said. "However, ordinary stellar-collapse channels, particularly those involving low-mass progenitors, can also produce neutron stars with masses of approximately 1.1 to 1.4 solar masses, so a low mass alone would not uniquely indicate an AIC origin."

The team isn't done investigating AICs, with Thümmler explaining there are two main approaches to take next.

"The first is to make the predicted light curves more reliable by following both the radioactive heating and energy injection in substantially greater detail," Thümmler said. "This requires distinguishing energy carried by gamma rays, which can escape relatively early from the low-mass ejecta, from that deposited more efficiently by charged particles, while also modelling how the neutron star wind heats and accelerates the heavy-element-rich material."

The team's simulations can then be used to follow the expansion of the ejecta from the AIC and calculate how the observed light curve and spectra depend on viewing angle.

"This work is currently underway," Thümmler said. "The second direction is to test the robustness of the explosion geometry, since our present models begin with a relatively simple magnetic-field configuration and more complex or tilted fields may produce different angular ejecta patterns."

The team's research is available to view as a pre-print on the paper repository site arXiv.

On clear September evenings, I often find myself looking up just after dusk, expecting the sky to feel a little less like summer. Yet there, still commanding the overhead darkness, are Vega, Altair, and Deneb — the three brilliant stars of the famous Summer Triangle.

Their familiar pattern can make the season feel as though it is lingering above us, even as cooler nights and earlier sunsets suggest otherwise. In fact, even as late as mid-November, the Triangle is still nearly overhead soon after sunset at dusk. That contrast raises a simple but intriguing question: if this bright celestial landmark remains so prominent well into autumn, why do we still call it the Summer Triangle?

Why not simply call it the Autumn Triangle?

Why it belongs to summer

The answer lies not in the calendar, but in how the Triangle moves across the sky over the course of a summer night. The chief reason is that, at this time of year, the Triangle does not remain visible all night. By dawn, it has begun to drop beyond the west-northwest horizon. During summer, by contrast, it remains with us from dusk until dawn: already evident in the east-northeast at nightfall, near overhead around the middle of the night, and descending in the west-northwest as daybreak approaches.

A matter of distance and brightness

The stars that compose the Triangle — Vega, Altair, and Deneb — lie at very unequal distances from us, so their apparent brightness can give a misleading impression of their true luminosity.

The closest of the three is Altair, 16.7 light-years away, followed by Vega at 25 light-years. Deneb, however, is vastly farther off, at roughly 1,600 light-years, though various sources place it between 1,400 and 2,600 light-years. Even though we see Deneb by light that may have begun its journey during the last days of the Roman Empire, it still shines at first magnitude (+1.3, to be exact) because it is a brilliant blue supergiant, at least 55,000 times brighter than the sun.

But their apparent superiority is largely a consequence of distance: Vega and Altair are only a few dozen light-years away, while Deneb lies well over a thousand light-years from Earth. Compared with the stellar lighthouse of Deneb, Vega and Altair are, comparatively speaking, penlight flashlights.

How to say "Vega"

Before continuing with this discussion about the Summer Triangle, it is worth pausing briefly on the pronunciation of Vega, a point that became especially noticeable after the 1997 science fiction drama Contact. Based on Carl Sagan's 1985 novel, the film follows astronomer Dr. Ellie Arroway, played by actress Jodie Foster, as she discovers a radio signal from Vega containing a sequence of prime numbers.

Throughout the film, the star is pronounced "Vey-gah," perhaps echoing Chevrolet's Vega, the subcompact automobile sold in the 1970s. Astronomers, however, generally use a different pronunciation.

The traditional astronomical pronunciation is Vē-ga, with the stress on the first syllable. In professional astronomical usage, Dr. Arroway and her colleagues would almost certainly have said "Vee-ga," not "Vey-gah." George Lovi (1939—1993), who was widely respected for his knowledge of star nomenclature, often reminded audiences that "Vee-ga is a star and Vey-gah is a car."

Who named the Summer Triangle?

There has long been debate over who first christened the bright stellar trio of Vega, Deneb, and Altair as the Summer Triangle. Some credit the legendary British astronomer Sir Patrick Moore (1923—2012), who wrote, "During a 1958 television broadcast on the BBC, I introduced the nickname of the Summer Triangle, and everyone now seems to use the term, even though it is completely unofficial." Yet several years earlier, in his 1952 sky guide, The Stars — A New Way to See Them, H.A. Rey (1898—1977) referred to the three stars as a "right triangle," and in his 1954 children's book, Find the Constellations, Rey used the Summer Triangle moniker.

Still others believe the term was popularized through U.S. navigator training manuals during World War II. Interestingly, astronomer Oswald Thomas (1882—1963) described Vega, Altair, and Deneb as "Grosses Dreieck" ("Great Triangle") in the late 1920s and as "Sommerliches Dreieck" ("Summerly Triangle") in 1934.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope, The Old Farmer's Almanac and other publications.

Using the ALMA (Atacama Large Millimeter/submillimeter Array) radio telescope, astronomers have watched as two stars come together to form a massive stellar binary. The observations revealed that these stars didn't form from the same collapsing cloud of gas and dust, as most binary stars are assumed to form, but instead came together later in their infancy.

Here on Earth, we are slightly prejudiced by our single sun to view stars as somewhat solitary bodies. However, around half of sun-sized stars in the Milky Way have a companion star. This percentage of stellar partnership rises to around 90% of massive stars. Eventually, these massive stars go supernova and shape their cosmic surroundings. Thus, understanding these binary systems is vital to our understanding of stars and of galaxies in general.

The team behind this research initially observed the still-growing massive stars, or protostars, in the binary system IRAS 07299−1651, located around 5,300 light-years away in 2019. At first, the researchers didn't see anything that suggested these stars didn't form from the same disk-shaped cloud of gas and dust that later fragmented. However, one thing really stood out: the disks of material surrounding and feeding these protostars are oddly misaligned.

Over the course of eight years, the team mapped subtle shifts in the position of the stars using ALMA in addition to the Very Large Array (VLA), as well as infrared images from the James Webb Space Telescope (JWST) and the Very Large Telescope (VLT).

"For the first time, we were able to watch two massive stars move around one another while they were still being born," team leader Yichen Zhang of Shanghai Jiao Tong University, China, said in a statement.

The team was able to reconstruct the full 3-dimensional structure of IRAS 07299−1651 for the first time, obtaining details about how the stars orbit each other, the way their disks are aligned, and the angle at which they blast jets into space.

"Each telescope revealed a different piece of the puzzle," team member Rubén Fedriani, of the Instituto de Astrofísica de Andalucía (IAA) in Granada, Spain, said. "The combination of radio and infrared observations provides the most exquisite detail on the formation of this massive protobinary system."

Unexpected chaos

The team's observations took them by surprise. They were expecting these stars to orbit each other in neat, near-circular orbits. Instead, the orbits were found to be highly flattened or "eccentric," almost parabolic.

If the stars had formed from the same disk of material, then even after it fragmented, the individual disks surrounding the stars would be aligned. However, that wasn't the case; the disks are tilted at a sharp angle to each other and to the orbits of the stars.

"It felt like solving a three-dimensional puzzle," team member Yao Wang of Shanghai Jiao Tong University said. "Each new observation added another piece, and eventually the orbit, disks, and jets all came together into a single, coherent picture."

The chaotic structure of IRAS 07299−1651, as observed by the team, is difficult to explain if the two stars emerged from the same disk of material.

Instead, the researchers theorize that the two stars were born in individual clouds of gas and dust, before a chance encounter brought the two infant stars and their respective natal cocoons together.

Tracing back the orbits of the stars, the researchers found that this encounter likely occurred around 60 years ago. Considering stars live for billions of years, that is an instant on a cosmic timescale. The disk-shaped pockets of material around the stars have thus far survived the encounter, retaining their well-defined structures.

"This study demonstrates that the early lives of stars can be quite chaotic, with a chance encounter leading to this gravitational dance and stellar coupling," team member Jonathan C. Tan of the University of Technology and the University of Virginia said.

What the team can't yet establish is whether these stars are destined to stick together or if they will eventually move apart. Indeed, this fate may not have been sealed yet; interactions with the surrounding gas could determine what shape this system takes in the future.

The team hopes that further observations of IRAS 07299−1651 will help to better understand what the future holds for these stars.

In the meantime, the long-term monitoring approach adopted by the researchers could provide scientists with a powerful new way of investigating other young massive binary systems. This could reveal how common encounters like this are and if more binary systems are composed of stars brought together by chance encounters.

The team's research was published on Tuesday (Sept. 8) in the journal Nature Astronomy.

Scientists are closer than ever before to understanding how stars forge the elements that comprise our planet, bodies and pretty much everything else around us — and they're gaining a clearer picture of where star explosions fit into the story.

New research reported in two different papers looks at how stars forge elements as they explode and how these supernova explosions spread those elements — and other elements stars have forged during their lifetimes — throughout the cosmos.

Astronomers have been studying the bright supernova deaths of massive stars for centuries, but they still don't quite understand how these explosions proceed.

The first paper looked at one way to investigate supernovas. It uses a radioactive element produced by these explosions called titanium-44, which lingers long after supernovas fade. Researchers have now collected experimental evidence that determines how much titanium-44 is created in a supernova, finding that these cosmic explosions produce 35% more of this element than expected.

With this knowledge in hand, scientists can now develop robust computer models of supernovas and compare these models with astronomical observations. This could bring them much closer to understanding how these explosions progress.

"It's exciting to see just how far the field has come," Christopher Cousins, a postdoctoral researcher in the University of Surrey's Nuclear Physics Group, said in a statement. "A measurement like this would have been considered out of reach only a couple of decades ago, but it now gives us new insight into one of the biggest unanswered questions in astrophysics."

The second paper honed in on a particular brand of stellar explosion called a Type I supernova. These occur when a dense stellar remnant called a neutron star drags material from a companion stellar body. The intense gravitational influence of the neutron star — a stellar corpse that has one to two times the mass of the sun crammed into a body about 12 miles (20 kilometers) wide — means that, when this stolen stellar matter hits their surfaces, a thermonuclear explosion is triggered.

These blasts forge heavy elements and release incredible amounts of energy, some in the form of X-ray bursts.

The authors of this paper, hailing from the Facility for Rare Isotope Beams (FRIB) in Michigan, studied the nuclear reaction that triggers X-ray bursts in greater detail than has been possible before.

This revealed the long-debated role of the so-called nickel-copper cycle, the temporary trapping of nuclear material during supernovas. Scientists previously didn't know if material was trapped in the nickel-copper cycle during X-ray bursts.

This research reveals that this does happen, but only in small proportions. It gives scientists a clearer picture of how Type I supernovas proceed.

"Despite decades of research, we still don't fully understand the nuclear reactions that power some of the universe's most spectacular stellar explosions," said Gavin Lotay of the University of Surrey.

"These two studies give us a much clearer picture of how these explosions happen, allowing us to compare our models more closely with astronomical observations and bringing us closer to understanding how the chemical elements are created and spread throughout the universe," he added.

The two papers were published in the July edition of the journal Physical Review Letters.

Betelgeuse may be a well-known and often-studied stellar object, but that doesn't mean astronomers aren't capable of capturing this doomed star in a completely new light.

A team of scientists examined the doomed red supergiant star with the Atacama Large Millimeter/submillimeter Array (ALMA), gaining new, highly detailed insights into its turbulent surface.

Betelgeuse, located around 600 light-years away, captured the public's attention a few years ago when the rapid and dramatic dimming of the infamous highly evolved star led some scientists to hypothesize that it was about to explode in a spectacular supernova. That hasn't happened, and scientists are now less convinced that this explosion is immediately imminent, but Betelgeuse remains the subject of intense scientific scrutiny.

"Its eventual fate as a supernova makes it fascinating to know what it actually looks like now," team leader Bill Dent, an astronomer at the European Southern Observatory (ESO), said in a statement.

The newly released ALMA images of Betelgeuse, captured in 2023, show bright hotspots on the star's surface and an almost corrugated texture arising from vast amounts of plasma shifting through the star, which has around 20 times the mass of our sun, but is puffed out to around 800 times the size of our star.

The observations show the red supergiant has an atmosphere with a temperature of around 3,680 degrees Fahrenheit (2,030 degrees Celsius), but possesses at least two regions even hotter than this. One of these areas is 980 degrees Fahrenheit (530 degrees Celsius) hotter than the plasma surrounding it.

The uneven nature seen by ALMA is likely the result of massive convective movements in the star, hot plasma rising through the star and generating shockwaves that erupt in the star's atmosphere, creating bright and hot regions.

The familiarity of Betelgeuse to astronomers doesn't mean the star isn't capable of delivering surprises too. When the team compared images collected in 2023 to observations from 2015, they were surprised to see a hotspot in the northeast of the stellar disk has persisted for at least seven years, that is much longer than predicted by current stellar models.

The orientation of the hotspots of Betelgeuse also added support to the idea that the red supergiant star is orbited by an elusive companion star.

Astronomers will continue to monitor the hotspots of Betelgeuse with ALMA to determine how fixed they are and how their evolution relates to things like mass loss, and the structure of the star's atmosphere.

That investigation will likely continue until Betelgeuse finally ends its life in a supernova explosion.

The team's research has been accepted for publication in the journal Astronomy & Astrophysics and is available on the paper repository site arXiv.

Astronomers have found the fastest known star in the Milky Way, a faint object racing around Sagittarius A*, the supermassive black hole at the heart of our galaxy. Dubbed S301, the star reaches about 15,500 miles (25,000 kilometers) per second at its fastest — more than 8% the speed of light.

"What is special about this star is that it's orbiting Sagittarius A* on a very tight orbit, taking just 8.7 years to complete it, and is approaching the black hole at a mere 12 times the distance of Earth to the sun. That is unprecedented," study author Felix Mang, a Ph.D. student at the Max Planck Institute for Extraterrestrial Physics in Germany, said in a statement.

The discovery gives astronomers a new way to probe the roughly 4.3-million-solar-mass black hole. General relativity predicts that a rotating black hole drags spacetime along with it, an effect known as frame dragging, or Lense-Thirring precession. That distortion should gradually alter S301's orbit — because the star ventures so close to Sagittarius A*, those changes may become measurable within about a decade.

For the first time, we would actually be able to measure very directly the spin of a massive black hole, which would be a key test of Einstein's theory," said study co-author Stefan Gillessen, also of the Max Planck Institute.

Researchers spotted S301 in 2023 using the GRAVITY instrument on the European Southern Observatory's Very Large Telescope Interferometer in Chile, then traced it back through observations from 2021 and 2017. Its highly elongated orbit suggests S301 may once have belonged to a binary system that wandered too close to Sagittarius A*. The black hole could have captured S301 while flinging its companion outward at tremendous speed.

Astronomers plan to keep tracking S301 with GRAVITY+ and, eventually, ESO's Extremely Large Telescope. With its next close pass expected in 2031, observations spanning two full orbits could reveal Sagittarius A*'s spin for the first time.

The team's research was published on August 19 in the journal Nature.

Astronomers have watched a dead star, in the guise of the Helix Nebula, being recycled back into the interstellar gas from which it originally came, bringing the story of that star full circle.

Stars can last for millions, or even billions, of years, but they do not last forever. When a sun-like star reaches the end, it blossoms into a beautiful planetary nebula. The Helix Nebula, located 650 light-years away in the constellation of Aquarius, the Water Bearer, is one such example of a planetary nebula.

The Helix's central star has run out of hydrogen needed for nuclear fusion reactions in its core. This caused the core to begin to contract and raised the temperature in the star's outer layers, which ignited fusion reactions there instead. This had the effect of causing the star to bloat into a red giant. Then, eventually, the outer layers of that red giant detached and expanded into space to form the Helix Nebula. Meanwhile, the star's inert core contracted and became a white dwarf.

As the nebula expands, it gradually disperses into the interstellar medium (ISM), feeding the elements formed within the star back into interstellar gas clouds. These clouds will eventually produce the next generation of stars. However, astronomers had never actually seen the point at which a dead star's remains are absorbed into the ISM — until now.

"We are seeing material shed near the end of a star's life being broken apart and returned to the galaxy," said Yale University's Pieter van Dokkum, who led the study, in a statement. "That hand-off — from recognizable stellar debris to the diffuse gas between the stars — has been very difficult to observe."

Van Dokkum's team were not actually looking for this. Instead, they were conducting routine calibration of a new astronomical instrument called MOTHRA, the Modular Optical Telephoto Hyperspectral Robotic Array at the El Sauce Observatory in Chile. When complete, MOTHRA will be armed with 1,140 telephoto lenses that will scrutinize the night sky while looking for traces of faint gas in the Milky Way galaxy.

Astronomical instruments require calibration before use, and this is accomplished by targeting a familiar object in the sky and tuning the instruments to how that object should appear. The MOTHRA team used the Helix Nebula to calibrate the telephoto lenses that they currently have operational, and that was when they found something unexpected.

"We thought we were taking a calibration image of one of the best-known nebulas in the sky," Roberto Abraham of the University of Toronto said in the statement. "Instead, we found this extraordinary network of bow-shaped structures. It was immediately clear that the faint outer Helix was telling us a story that had largely been missed."

The Helix Nebula appears donut-shaped and has been imaged countless times before by both professional observatories such as the Hubble Space Telescope and James Webb Space Telescope, and by amateur astronomers whose long exposures can reveal an outer halo of gas around the nebula's bright ring. To give an idea of scale, the outer edge of the bright ring is 5.7 light-years across, and the outer halo exists beyond even this.

The team discovered 22 complete or partial arc-shaped clumps of gas in the outer halo. They are called bow shocks and they arise from the motion of something pressing into another medium, in this case clumps of gas that have expanded out from the planetary nebula running into and plowing through the ISM. It is similar to the bow-shaped waves that ride ahead of the prow of a boat in water.

"The shocks change dramatically with distance from the central star," Imad Pasha of Dragonfly Focused Research Organisation, said in the statement.. "Those nearer the center are large, thin and sharply defined. Further out, they become smaller, fuzzier and increasingly fragmented."

This implies a progression, and that the deeper into the ISM the clumps of the star's ejected material press, the more they become eroded and dispersed back into the interstellar gas. The team estimate that material from the planetary nebula can survive for about 10,000 years after encountering the ISM before they are completely shredded and absorbed back into it.

Stars are born from the molecular gas clouds that lie in interstellar space, and these clouds are enriched with the elements produced by fusion reactions within previous generations of stars. Now, thanks to MOTHRA's observations of the Helix Nebula, we have seen these elements being gifted to the Milky Way at large, and in millions or billions of years they will contribute to a new generation of stars, planets and possibly life.

Our own solar system, and Earth along with it, were formed 4.6 billion years ago from elements produced by dead stars. In another five billion years' time, our sun will also exhaust its supply of hydrogen and its fusion reactions will cease, causing it to unfurl into its own planetary nebula.

"Far in the future the sun will go through a similar process and its material will enter the same cycle," says van Dokkum.

All the elements and molecules that make up you and everything around you will be given back to the Milky Way, and one day it will be reborn again and begin the story of a new star system. What will that story bring, we wonder?

The findings from the Helix Nebula were published on Aug. 12 in the journal Nature.

Empty space is not as empty as it looks.

That is the takeaway of a new study examining signals from a dead star, offering what researchers say is the strongest evidence yet that extreme magnetic fields can alter the properties of a vacuum, causing seemingly empty space to act like a prism and changing how light travels through it

The findings, led by Rachael Stewart, a graduate student in physics at the George Washington University, confirm a prediction of a strange effect first proposed 90 years ago.

"The information we obtained from looking at this distant star core also gives us clues about the nature of the fabric of reality as we know it, and I find that to be incredible," Stewart said in a statement.

The idea dates to 1936, when the German physicist Werner Heisenberg and his student Hans Euler proposed that space is never truly void. Instead, they argued, it is a simmering sea of "virtual particles" — electrons and their antimatter counterparts, positrons — that flicker in and out of existence, briefly interacting with their surroundings before vanishing.

This subatomic froth is a consequence of quantum mechanics, and it remains invisible under ordinary conditions. But the theory predicts that an extremely strong magnetic field, such as one around a magnetar, can change how light moves, causing the light's waves to become more strongly aligned in a particular direction in an effect known as "vacuum birefringence."

"Detecting vacuum birefringence requires a magnetic field that is over 100 million times stronger than any we've ever made on Earth," study co-author Marcus Lower, an astrophysicist at the Swinburne University in Australia, said in another statement. "Thankfully, nature has provided us with magnetars, which are the perfect cosmic laboratories to go looking for this effect."

Magnetars are dense, city-size remnants left behind after massive stars explode, hosting the most powerful magnetic fields known in the universe. They are among the rare celestial objects capable of generating fields strong enough to reveal vacuum birefringence, offering scientists an extreme environment to test physics under conditions impossible to replicate on Earth.

"We're not just studying astronomical objects anymore; we're using them to test the laws of nature," study co-author Michela Negro, an astrophysicist at the Louisiana State University, said in a statement.

Astronomers have caught glimpses of this elusive phenomenon before, but not conclusively. In 2017, researchers using the Very Large Telescope in Chile observed polarization hints around a faint neutron star called RX J1856.5-3754, located about 400 light-years from Earth. However, those optical measurements remained open to interpretation, partly due to the challenges of isolating the optical signal.

At the time, scientists noted that definitive proof would require space-based X-ray observatories, specifically NASA's then-forthcoming Imaging X-ray Polarimetry Explorer (IXPE). Launched in 2021, IXPE carries three identical telescopes designed to measure the polarization of high-energy X-rays.

"It's only in the last six or so years that we've actually had a telescope capable of detecting this effect around magnetars," Lower told Michael West Media, an independent news website in Australia.

In March and April 2025, the researchers pointed IXPE at 1E 1547-5408, a magnetar that spins once every two seconds and is unusual among its kind for steadily emitting radio waves. The team supplemented that data with observations from an X-ray telescope aboard the International Space Station, as well as Australia's Murriyang radio telescope and the South African Radio Astronomy Observatory.

According to the study, two findings pointed to vacuum birefringence at work.

First, the X-rays picked up by IXPE were nearly three times more polarized than in similar sources, far higher than standard models of a neutron star's surface emission could explain on their own. Second, the polarization pointed the same way as the star's magnetic field, matching the pattern already observed in its radio waves. The researchers concluded that this combination leaves vacuum birefringence as the only explanation that fits the data.

"It's a bit of a relief because it means that our theories still work and there's nothing broken with physics," Lower told the Michael West Media news site.

For Fernando Camilo, chief scientist at the South African Radio Astronomy Observatory and a co-author of the new paper, the discovery brings a long journey full circle. Camilo has been studying 1E 1547-5408 since 2007, when he first detected its radio waves using the Murriyang dish, revealing its two-second rotation rate.

"At the time 1E 1547 was only the second magnetar in the Milky Way known to emit radio waves, and we were confident that regular monitoring would unveil interesting behaviour," Camilo said in the statement. "However we could never have imagined that 20 years later it would contribute to investigating a fundamental, and particularly quirky, prediction of quantum mechanics."

The team hopes to confirm the finding with data from future missions, including a proposed orbital mission called GoSOX (short for Globe Orbiting Soft X-ray Polarimeter), alongside improved computer simulations to distinguish the vacuum birefringence signal from other processes around magnetars.

"With these future data on hand and our updated simulations, we may finally be able to complete the quest started by Heisenberg nearly 90 years ago," Lower said in the Swinburne University statement.

This research is described in a paper published Aug. 5 in the journal Nature.

The heart of the Milky Way may be more hospitable to water than astronomers thought.

Using the James Webb Space Telescope (JWST), researchers detected water and cosmic dust around an aging star only 0.55 light-years from Sagittarius A* (Sgr A*), the supermassive black hole at the center of our galaxy.

The new study suggests that water and dust can form and survive surprisingly close to a supermassive black hole, where intense radiation and other harsh conditions might otherwise be expected to destroy them. The team used Webb's Mid-Infrared Instrument (MIRI) to study IRS 3, an aging star located in the crowded environment surrounding Sgr A*, which has a mass of about 4 million suns, according to a statement from the European Space Agency (ESA).

"Galactic centres are among the most extreme environments, so understanding whether stars can continue enriching their surroundings there is an important question," Florian Peißker, lead author of the study from the University of Cologne in Germany, said in the statement. "With Webb, we can directly observe how stars behave under these conditions and see that dust production remains remarkably resilient."

IRS 3 — one of the brightest mid-infrared sources in the galactic center — is an asymptotic giant branch star, meaning it has reached a late stage of stellar evolution in which it sheds large amounts of gas and dust through powerful stellar winds. Such dying stars act as cosmic recycling centers, returning material to space that can eventually become incorporated into future generations of stars and planets.

But IRS 3 lives in a particularly unforgiving neighborhood. The center of the Milky Way is densely packed with stars and exposed to intense radiation, raising questions about whether molecules and newly produced dust can persist there.

However, Webb's observations suggest they can. By combining observations of IRS 3's spectrum with simulations of how its light travels through different models of the surrounding material, researchers reconstructed the structure of the star's envelope. They found a layered, shell-like distribution of silicate dust extending roughly 10,000 astronomical units from the star (one astronomical unit, or AU, is the average distance between Earth and the sun). Temperatures within the envelope fall from about 1,700 degrees Fahrenheit (927 degrees Celsius) near the star to around minus 280 F (minus 173 C) in its outer regions. Webb's observations also revealed clear evidence of water within the envelope — the first such detection for IRS 3.

"The detection of water is especially exciting because it shows that molecular material can survive in an environment dominated by intense radiation," Macarena Garcia Marin, co-author of the study and an ESA astronomer, said in the statement.

While the observations don't reveal how much water is present, the detection shows that water can survive in the harsh environment near the galactic center. Water and dust are important ingredients in the chemistry that accompanies star and planet formation, meaning material shed by aging stars such as IRS 3 could eventually contribute to future generations of stars and planets.

Finding water and dust near Sgr A* therefore suggests that aging stars can continue enriching their surroundings even in the harsh conditions near a supermassive black hole. The findings could help astronomers better understand how material is recycled in the centers of galaxies and the role evolved stars play in supplying those regions with fresh dust and molecules.

Their findings were published Aug. 11 in the journal Astronomy & Astrophysics.

In a nebula far, far away, colossal clouds of dust and gas tower amongst the stars.

What is it?

This spectacular new image from the James Webb Space Telescope showcases the brilliant majesty of the Carina Nebula, a giant cloud of dust and gas found 7,500 light-years away in the constellation Carina.

You may have seen the Carina Nebula before — in the first-ever image released from JWST, which has been dubbed "Cosmic Cliffs."

In this new image, captured by JWST's Near-Infrared Camera (NIRCam), you can see the nebula in a whole new light. This snapshot captures a specific feature that is being dubbed the "Treasure Chest," as it vaguely resembles a glowing coffer overflowing with stellar jewels.

This "Treasure Chest" contains a cluster of young stars, approximately 70 stars in total. While these might be young, growing stars, the most massive of the bunch is a whopping 19 times more massive than our sun.

Why is it incredible?

While JWST has looked at the Carina Nebula before, new observations can reveal completely new details and help scientists uncover new information about the nebula and the strange ways in which the universe works.

Right now, scientists think that the star cluster in the "Treasure Chest" is about 1.3 million years old. However, previous estimates thought the grouping could be just 100,000 years old. So, new observations by powerful telescopes like JWST can significantly change our understanding of the cosmos.

With each new observation or data point, the history and context of the universe around us could completely transform. And, as this star cluster grows over time, its stars will become more brilliant. They may therefore illuminate more of this star cluster, potentially revealing details and secrets of this "treasure" that scientists might never have predicted.

Astronomers have captured the death of a massive star from its first faint flash of X-rays, revealing an unusual explosion that may bridge the gap between ordinary supernovas and more extreme, gamma-ray-burst-producing stellar explosions

The event began in March 2026, when China's Einstein Probe spacecraft detected a brief X-ray flash from a galaxy about 500 million light-years away. Follow-up observations identified the source, initially designated EP260321a and later named supernova SN 2026gzf, as a broad-lined Type Ic supernova.

Such explosions occur when massive stars that have lost their outer layers of hydrogen and helium collapse. They are often associated with narrow, powerful jets traveling near the speed of light and, in some cases, brilliant gamma-ray bursts. But SN 2026gzf produced neither.

Instead, the initial X-ray signal appears to have been a "shock breakout" — the moment the blast wave generated by a collapsing star reaches its surface and releases its first burst of radiation. The flash was the faintest shock breakout yet linked to a broad-lined Type Ic supernova, according to the research team.

Because shock breakouts generally last only seconds to hours, astronomers rarely detect them. In this case, rapid observations by a network of space- and ground-based telescopes, including a number of NSF NOIRLab observatories, allowed researchers to follow the supernova across multiple wavelengths throughout its early life.

"Our observations allowed us to study the physics of three pieces of this explosion: the X-ray shock breakout, the accompanying supernova, and the interaction of the supernova with material previously cast out by the dying star," Jillian Rastinejad, who led one study on the event, said in a statement. "With this information we were able to map out the structure of the material surrounding the star and understand the star's violent lifestyle before it collapsed."

The observations suggest that the progenitor was a Wolf-Rayet star born with about 20 times the mass of the sun. Before exploding, it had shed its hydrogen and helium, leaving behind a core composed largely of carbon and oxygen.

Researchers also found evidence of multiple shells of material surrounding the star. Those shells were likely expelled during turbulent bouts of mass loss shortly before the explosion, giving astronomers an unusually detailed view of the star's final stages.

The discovery suggests that energetic, broad-lined Type Ic supernovas do not always produce gamma-ray bursts or relativistic jets. Instead, massive stars may reach similar-looking explosions through a wider variety of pathways than astronomers previously recognized.

"Going forward, I'm excited to observe more shock breakout events in similar detail to test if all stripped stars have a similar 'lifestyle' prior to collapse and what, if any, differences we see," said Gokul Srinivasaragavan, a member of Rastinejad's team.

Astronomers have used the Very Large Telescope (VLT) in the Atacama Desert region of Northern Chile to discover the strongest evidence yet that the famous star Betelgeuse has a companion star. That means after a century of investigation, scientists are closer than ever before to conclusively identifying Betelgeuse as a binary system composed of two stars, Betelgeuse A and Betelgeuse B.

Betelgeuse is a red colored star visible with the naked eye in the constellation of Orion and located around 650 light-years from Earth. Astronomers initially proposed the existence of another star orbiting Betelgeuse around 100 years ago in an attempt to explain the familiar star's strange dimming, which has been observed for over 1,000 years. While other teams have gathered evidence of the existence of Betelgeuse B, this new image is the clearest ever direct observation of the star. The scientists behind the discovery are thrilled.

"This is the conclusion of a century-long quest," team leader Miguel Montargès of the Observatoire de Paris, France, said in a statement. "We have shown that Betelgeuse is not single; it is accompanied by a faint stellar companion. I jumped from my chair when I saw the processed images."

The discovery of this new evidence of Betelgeuse B follows two papers published in 2024 that suggested this elusive stellar companion would be at its furthest from Betelgeuse A in December of that year. With that clue in hand, Montargès and colleagues set about hunting it.

"Honestly, I thought we did not have the sensitivity to detect Betelgeuse B as it was predicted," Montargès said. "Because it is more massive than predicted, we see it!"

Betelgeuse B had previously been theorized to be around the same mass as the sun, but these new observations reveal that this elusive star has instead around two to three times the mass of our star.

"The fact that we can still discover a nearby companion, more massive and brighter than the sun, around such a well-studied star is remarkable," Montargès added. "These are among the best moments in science: seeing something new, unexpected."

Capturing Betelegeuse B was only possible thanks to the VLT's SPHERE instrument, which features a coronagraph that blocks out the light of a planetary system's star. Combined with the advanced optics on the instrument, this allows scientists to measure the wavelength and polarity of light both coming directly from the star and being reflected off of any nearby planets. But that's not all SPHERE can do.

"It is remarkable to see how SPHERE and advanced post-processing techniques, originally developed to find exoplanets, also excel at detecting a companion around a massive, evolved star like Betelgeuse," team member Anthony Boccaletti, also an astronomer at the Observatoire de Paris, said.

There are still many questions to answer regarding Betelgeuse B. The team still needs to solidly confirm that what they have seen is actually a companion star, and they would also like to know how the presence of this star could shape the future of Betelgeuse A.

This red supergiant star nearing the end of its evolution gained notoriety a few years ago when its sudden and rapid brightening led to speculation it was about to suffer an explosive death.

"To be certain that the companion is really there, we still need to observe it in one year on the other side of the star, but there is very little space left for doubt," Montargès said. "The question is truly open whether this companion is going to have an impact on the evolution of the red supergiant."

The team's research was published on Tuesday (July 28) in the journal Astronomy & Astrophysics.

For the first time, scientists may have discovered a binary system—like the twin suns of the fictional planet Tatooine in "Star Wars"—where both stars exploded as supernovas, a new study finds.

Although Earth may orbit around a single star, more than half of all stars are in systems where two or more suns orbit each other. "When it comes to massive stars, the percentage in multiple systems are even higher," study lead author Miltiadis Michailidis, a postdoctoral fellow at Stanford University in California, told Space.com.

When massive stars burn all their fuel, they can die in giant explosions known as supernovas. These outbursts can briefly outshine all of the other suns in these stars' galaxies. They often leave behind expanding super-hot clouds of debris known as supernova remnants. Astronomers have detected about 300 such remnants in our galaxy to date.

Given how often massive stars are found in binary systems, "one can expect many pairs of massive stars where both will explode as supernovas," Michailidis noted. "However, this has never been observed, until now."

One reason supernova pairs may have escaped attention is that "if the stars are too close together when they exploded, the resulting supernova remnants may look like that from a single explosion," Michailidis explained. Another is that one star going supernova may propel its partner far enough away to hide the fact they were ever a duo, he added.

In the new study, Michailidis and his colleagues investigated a supernova remnant known as IC 443, located about 6,000 light-years from Earth in the constellation Gemini. IC 443 is also known as the Jellyfish Nebula for how it resembles a jellyfish.

IC 443 is one of the most extensively studied supernova remnants in the galaxy because of how shock waves from the supernova have collided with surrounding clouds of gas and dust to create a set of concentric bubble shells, "much like how a drop of water falling on a lake creates circular waves," Michailidis said. "It is very isolated from its surroundings, without many other objects nearby to complicate its very bright emissions."

The scientists analyzed one of IC 443's much dimmer, long-hidden neighbors, dubbed G189.6+3.3. The German-led ROSAT (Roentgen Satellite) mission first discovered G189.6+3.3 in 1994 via its faint X-ray emissions, and the Russian-German Spektrum Roentgen Gamma (SRG) space observatory later clearly detected shell-like structures within G189.6+3.3, suggesting that it was a supernova remnant.

In the new study, the researchers analyzed more than 16 years of data from NASA's Fermi Gamma-ray Space Telescope along with earlier X-ray, optical and radio measurements. They discovered signs that both IC 443 and G189.6+3.3 were both smashing into the same interstellar cloud of hydrogen, revealing they were close together in space, with the centers of their explosions about 30 to 50 light-years apart.

The researchers calculated that the chances of randomly encountering two unrelated supernova remnants at this distance from one another "was about one in 1,000," Michailidis said. "This suggests that our discovery is in fact the first known binary-system supernova pair."

The scientists estimated that G189.6+3.3 was older than IC 443, with the parent star of G189.6+3.3 exploding between 20,000 to 110,000 years ago, while IC 443 was created about 8,000 to 9,000 years ago. The original stars may have been 20 or more times the sun's mass.

These new findings can help shed light on how massive binary stars evolve, interact and die. For instance, further analysis of G189.6+3.3 and IC 443 can reveal how much of a kick the former gave the latter when it died, Michailidis said.

The scientists detailed their findings July 21 in the journal Nature Communications.

Reboots and remakes may be all the rage in Hollywood with mixed degrees of success (we don't talk about the Nightmare on Elm Street reboot ... ever), but they aren't so popular in other forms of art such as painting. However, a recent cosmic rework of one of art's most well-regarded pieces could be just as breathtaking as its original counterpart.

That's all thanks to the Dark Energy Camera (DECam), which has captured a vibrant view of the Corona Australis molecular cloud, that shows the star-forming region resembling a cosmic take on Vincent Van Gogh's iconic painting The Starry Night.

The Corona Australis Molecular Cloud measures around 16 light-years in diameter is located around 430 light-years from Earth, making it one of the closest star-birthing regions to our solar system. The molecular cloud and its dark lanes of gas and dust, the raw materials for star construction, are at the left of the DECam image.

Also prominent on the left of the image is the shining nebula NGC 6729, which is a reflection nebula of the Corona Australis Molecular Cloud. That means that it is a cloud of interstellar dust that is reflecting the light of the newborn stars embedded within this molecular cloud.

NGC 6729 is composed of different elements that can be seen on the left side of the image. This includes an orange cloud that is actually the binary star system R Coronae Australis. This binary consists of a pre-main-sequence star that has gathered mass but hasn't yet triggered the fusion of hydrogen to helium in its core, and its companion, a red dwarf star. These stars orbit each other every 43 to 47 years and are incredibly bright, with their light also reflecting from nearby reflection nebulas. This light also ionizes nearby gas, creating glowing regions called emission nebulae, also part of NGC 6729.

To the top-right of the image is the globular cluster NGC 6723, nicknamed the Chandelier Cluster. Located around 29,000 light-years from Earth, NGC 6723 is thought to contain some of the oldest stars in the Milky Way.

The Chandelier Cluster contains tens of thousands to millions of stars, which aren't all ancient; within the spherically shaped globular cluster are more than a smattering of younger stars.

Astronomers and astrophotographers of all levels will be more than familiar with the Corona Australis Molecular Cloud and the Chandelier Cluster and this region as a whole.

But just as it took the artistic vision of Van Gogh to transform the night sky into a stunning painting, it has taken the observing power of the DECam, mounted on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO) in Chile, to bring out the stunning beauty of this slice of the night sky.

Astronomers have spotted four dead star white dwarf stars playing a game of cosmic hide-and-seek, all four of which were hiding in the glares of red dwarf companion stars.

This marks the first detection of white dwarfs existing in double star systems in our cosmic backyard. The white dwarfs are all located within around 65 light-years of Earth, and one of them is number nine in the top 10 closest white dwarfs to the solar system.

White dwarfs are the type of stellar remnants left behind when stars around the size of the sun run out of fuel needed for nuclear fusion. This leads to their cores collapsing. The lack of fusion also means these stellar remnants cool and become dim. Thus, the light of much larger and brighter red dwarf stars is incredibly effective at hiding white dwarfs.

"Nearby isolated white dwarfs are usually easy to find, but we couldn't see these four stars directly in visible wavelengths because their red dwarf companions were drowning out their light," team leader Mairi O'Brien of the University of Warwick in the UK said in a statement. "It's a reminder that even in our own cosmic neighborhood, we can still find surprises if we look in the right way, at the right wavelengths."

Wobbles gave them away

Though astronomers have been diligently surveying our cosmic backyard for decades, white dwarfs are extremely good at remaining unseen. In fact, the only thing that gave these four hidden dead stars away? Curious "wobbles" caused in the motion of the stars they were hiding behind, like a hiding child causing a curtain to ripple.

The team followed up on these telltale clues by taking a closer look at these systems with NASA's long-serving Hubble Space Telescope. This investigation was conducted in ultraviolet light and using custom calibration to prevent flaring from the red dwarf companions from mimicking white dwarf signals.

This investigation not only revealed the four lurking white dwarfs, but also demonstrated that one of these systems, G 203-47, located just 25 light-years away, has some curious characteristics. Twenty-seven years elapsed between the initial radial wobble and the detection of this hidden dead star.

That isn't the weird thing, though. What is strange is that the red dwarf companion of this white dwarf only rotates once every 100 Earth days or so, yet it only takes about 15 days to orbit its dead star companion. This means that gravitational forces have failed to lock the red dwarf and white dwarf together, which is what happens in similar systems.

"What's fascinating is that G 203-47 shouldn't be rotating this slowly if it formed the same way as similar systems. This suggests that these binaries have had very different evolutionary histories," team member David Wilson, of the University of Colorado Boulder, said. "Some underwent violent, prolonged interactions early on that locked them tidally. Others, like G 203-47, experienced gentler, briefer encounters that left them in this unusual state."

The discovery of these white dwarfs helps researchers better understand the population numbers of the dead stars throughout the Milky Way. In fact, predictions would have suggested finding roughly four to five closely orbiting white dwarf-red dwarf pairs within around 65 light-years of our solar system, so finding four should instill a lot of confidence in our current theoretical models.

"Only about 30% of red dwarfs within 20 parsecs [65 light-years] have been systematically surveyed for hidden white dwarf companions," team member and University of Warwick researcher Pier-Emmanuel Tremblay said in the statement. "We think there could be as many as nine or 10 additional binary systems in our local stellar environment that we haven’t found yet.

"If we put more targeted effort into observing red dwarfs, perhaps we will find more surprises like this."

The team's research was published on Tues (July 14) in the journal Monthly Notices of the Royal Astronomical Society (MNRAS).

Astronomers have, for the first time, directly mapped the magnetic field surrounding an unusual "lighthouse" pulsar, revealing an invisible cosmic highway that channels particles blasted from the rapidly spinning stellar remnant.

Using NASA's Imaging X-ray Polarimetry Explorer (IXPE) mission, researchers measured the magnetic field around the pulsar PSR J1101−6101 — nicknamed the "Lighthouse" — and confirmed a long-standing prediction that its high-energy particles stream along magnetic field lines extending through the Milky Way. This discovery offers a rare look at how some of the universe's most extreme objects accelerate particles to nearly the speed of light, according to a statement from the space agency.

Pulsars are rapidly rotating neutron stars — the ultra-dense remnants left behind when massive stars explode as supernovas. Their powerful magnetic fields channel beams of radiation from their magnetic poles that sweep across space as the stars spin, much like the beam of a lighthouse.

PSR J1101−6101, which is located at the center of the Lighthouse Nebula, spins about 16 times every second and is traveling at supersonic speeds after receiving a powerful kick from the supernova that created it. As it tears through interstellar gas, it leaves behind a bright X-ray tail while producing a narrow filament that juts out almost perpendicular to its direction of travel. Astronomers had long suspected this unusual structure traced energetic electrons escaping along the Milky Way's magnetic field.

"We wanted to test that theory,"Jack Dinsmore, lead author of the study and undergraduate student at Stanford University, said in the statement. "The 'smoking gun' would come by measuring the polarization of the light, which indicates the magnetic field direction. If the magnetic field points along the filament, that confirms that the filament's particles are flowing along the field."

Unlike conventional X-ray telescopes, IXPE measures the polarization of X-rays — the preferred orientation of their electric fields — allowing scientists to reconstruct the geometry of otherwise invisible magnetic fields. Because the Lighthouse Nebula is relatively faint in X-rays, the researchers developed new analysis techniques to extract as much information as possible from the observations.

The team found that the magnetic field runs parallel to a remarkably long filament extending away from the pulsar, confirming that high-energy particles are streaming along magnetic field lines. But the observations also uncovered an unexpected twist: the field is far more orderly than scientists anticipated. The unusually strong polarization signal suggests the filament contains much less magnetic turbulence than current models predict, offering new insight into how fast-moving pulsars inject energetic particles into the surrounding galaxy.

"The striking divergence in magnetic field orientations observed between radio and X-ray wavelengths provides compelling evidence for the highly structured nature of these objects," Niccolò Bucciantini, co-author of the study from the Italian National Institute for Astrophysics, said in the statement. "This marks the first clear indication that particles of different energies occupy distinct regions within the system, hinting at the presence of multiple, and potentially very different, acceleration mechanisms at work."

Their findings were published July 9 in The Astrophysical Journal.

The universe is haunted by "cosmic ghosts" called neutrinos, and new research suggests they may be the "whispers" of stars that died in supernova explosions over the course of billions of years.

The discovery is an important step forward in our understanding of the life and death of stars and how they enrich their environments with metals, elements heavier than hydrogen and helium. It could also help better understand how black holes and neutron stars are born when massive stars die.

The second most common particles in the universe, neutrinos get their spooky nickname because they are chargeless and near-massless, so phantom-like that around 100 trillion neutrinos pass through you at nearly the speed of light every second, but over your entire life only one will interact with the atoms of your body, if you're lucky.

The newly suggested connection between neutrinos and a history of supernova blasts has emerged from the first detection of a flux of neutrinos called the Diffuse Supernova Neutrino Background (DSNB). It was detected by one of the world's largest neutrino detectors, the Super-Kamiokande, located 3,280 feet (1,000 meters) underground in Gifu Prefecture, Japan.

"Observing the world's first indication of the Diffuse Supernova Neutrino Background is a deeply meaningful achievement and has been a long-cherished goal since the beginning of the Super-Kamiokande project," Hiroyuki Sekiya of the University of Tokyo said in a statement.

Stars go out with a bang but continue with a whisper

Supernovas come in a range of types, but the ones this research concerns are so-called "core-collapse supernovas." These occur when stars much more massive than the sun reach the end of nucleosynthesis in their cores. When they are no longer able to fuse elements to create metals heavier than iron, the stars become unable to produce the outward energy that for millions of years has balanced them against the inward push of gravity.

Thus, with gravity the ultimate winner of this cosmic tug of war, the star's core collapses, sending violent shockwaves rippling outward into the outer stellar layers, which are ripped away. This leaves the core as a stellar remnant, either a neutron star or a black hole, initially surrounded by an expanding shell of supernova debris.

The energy from these events is carried away by particles of light (photons) spread across the electromagnetic spectrum, but also by neutrinos. Yet, despite the fact that supernovas have been erupting every second over the course of 13 billion years or so to produce the neutrinos that accumulate as the DSNB, this ghostly signal is still faint, a whisper rather than a shout.

To "hear" these cosmic whispers, the team behind this research analysed almost 14 years of data from Super-Kamiokande in the form of Cherenkov light generated when neutrinos interact with 50,000 tons of ultrapure water.

This revealed a signal of neutrinos in line with what would be expected from the DSNB. This signal still needs to be confirmed, but it is a strong indicator of the DSNB, the first humanity has ever had.

"We are already planning on incorporating ongoing observations at Super-Kamiokande together with its successor detector, Hyper-Kamiokande, to further improve sensitivity in future collaborative studies," said team member Yosuke Ashida,of Tohoku University.

The team's results were presented on June 25, 2026, at Neutrino 2026: XXXII International Conference on Neutrino Physics and Astrophysics, held at the University of California, Irvine, USA.

If the universe has one lesson for humanity, it is that everything ends. That includes stars, which too must die, albeit on timescales of billions of years. But new research suggests that when some stars die, they do not do so alone, potentially solving a long-standing mystery around a particular class of cosmic explosion called an interacting supernova.

When stars much more massive than the sun reach the ends of their lives, their cores collapse, sending shockwaves blasting out into their outer layers, triggering explosions called supernovas and leaving behind stellar remnants in the form of neutron stars or black holes. Interacting supernovas differ because the shockwave generated by these explosions crash into a pre-existing cocoon of material. The big mystery has always been: where does this cocoon of gas and dust come from?

Humanity is somewhat biased when it comes to stars; after all, the sun dominates our existence, and it is a solitary stellar body. But contrary to this, the majority of stars aren't so antisocial, existing in binary partnerships bound together by gravity. This new research suggests that these stars don't just live together; they can die together too. Understanding this dual existence could be key to solving the origins of dust shrouds in interacting supernovas.

"Our study suggests that many stars do not die alone," team member Ke-Jung Chen, of the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), said in a statement. "Their final appearance may be shaped by a long and intimate partnership with a companion star."

How somes stars become a drain

Before stars reach the ends of their lives, they enter a relatively short-duration red giant phase. This can see them swell out to hundreds or even thousands of times their original radius.

For a binary stellar pairing, this leads to a situation called "roche lobe overflow," which basically sees the swollen-out star spilling material onto its companion. However, not all of that material is captured by the companion star, escaping to form a vast cocoon around the binary stars.

When the evolved and swollen star reaches the end of its life and "goes nova," the shockwaves ripple forward and slam into this cocoon of matter at speeds of thousands of miles per second. The kinetic energy becomes light, creating a strange and intensely bright interacting supernova.

That leaves an obvious question, however. If stellar binaries are so common, and become even more common for stars massive enough to go supernova, why aren't interacting supernovas more common?

Turns out, just like with comedy, the secret is ... timing.

Chen and colleagues ran hundreds of computer simulations of mass transfer between binary stars and discovered that the key to generating an interacting supernova is when this mass transfer occurs late in the stars' lives.

If mass transfer occurs too early, say millions of years before the final supernova blast, the team found that the material spreads far away from the binary stars, dissipating the surrounding cocoon. For the cocoon to hang around for shockwaves to strike, mass transfer has to occur just a few thousand years before the final explosive death throes of one of the binary stars.

"We found that binary stars can prepare the stage for interacting supernovas with remarkable timing," team member Sung-Han Tsai of ASIAA said. "The companion star helps create a dense cocoon around the dying star just before the explosion, providing the fuel that powers these cosmic fireworks."

The team's research shows that there are many ways for stars to die, and these explosive fates are determined by the way they lived.

The team's research was published on June 30 in The Astrophysical Journal Letters.

Silent neutron stars at the center of supernova blast sites may actually be whispering softly, following the detection of faint radio emissions coming from one such object for the first time. The discovery raises the prospect that there could be many more pulsars in our galaxy than we thought.

When a massive star explodes as a supernova, the devastation leads to the star's core collapsing under its own gravity to form either a neutron star or a black hole. When a neutron star is formed, it is born spinning and its magnetic field is usually powerful enough to whip up charged particles and beam them away in a jet moving at close to the speed of light. This jet emits radio waves, and as the neutron star spins we see this radio jet flashing in our direction. This makes it seem like the neutron star is pulsing, hence we call it a pulsar.

Puzzlingly, not all neutron stars at the center of supernova remnants are pulsars. About a dozen discovered so far have been dead quiet in radio waves, and astronomers call these quiet neutron stars 'central compact objects', or CCOs. One possible explanation for CCOs is that their magnetic fields are too weak to produce detectable radio jets. For decades, astronomers have tuned into them, finding only radio silence  — until now.

A team led by Zhang Lei of the National Astronomical Observatories of the Chinese Academy of Sciences tuned into one particular CCO, named 1E 1207.4-5209 with the MeerKAT radio telescope in South Africa. They discovered that the CCO is pulsing with radio waves after all, but very faintly, once every 424 milliseconds. This matches the known spin period of the pulsar – it's a veritable whirling dervish.

Found at the center of a supernova found 10,000 light years away within our Milky Way galaxy, 1E 1207.4-5209 has been nicknamed the "Blue Eye Pulsar" by Li Di, a professor of astronomy at Tsinghua University in China. Its name is a virtue of the fact that when the faint radio emission is combined with X-ray images that show the neutron star shining brightly, it looks like a blue eye.

The Blue Eye Pulsar has an intriguing history. The supernova that formed it exploded over 4,100 years ago. In 2015, X-ray observations noted that the pulsar had experienced a 'spin glitch', which is a small increase in rotation of a neutron star probably caused by some kind of disruption or shifting of material within the neutron star's dense interior.

Lei's team propose that this glitch either strengthened or reoriented, or both, the magnetic field of the Blue Eye Pulsar sufficiently to trigger radio emissions, or at least make feeble radio waves that were already there detectable.

Following a glitch, a neutron star's rotation rate gradually slows back down to its original rate, at which point we might expect the Blue Eye Pulsar's radio emission to switch back off. Lei's team suggests that continued monitoring of the Blue Eye Pulsar could answer this question.

If that answer is what Lei's team think it to be, then it could mean that there is a large population of very feeble pulsars that remain undetected in the galaxy. Old pulsars, which persist long after the supernova remnant they were born in has dissipated, are also fairly quiet radio emitters because they are slowing their spin rate over time. However, it is possible that we have misidentified some of these pulsars as being old when they could in fact be relatively young but softly radio emitting.

The findings may also explain why some supernova remnants seem to be missing pulsars. Key among them is the expanding cloud of debris formed from the explosion of supernova 1987A in the Large Magellanic Cloud. Although astronomers are pretty sure there is a neutron star in the heart of the remnant based on indirect evidence, no pulsar radio emissions have yet been detected.

The detection of radio waves from the Blue Eye Pulsar was reported June 25 in Nature Astronomy.

Astronomers have used the James Webb Space Telescope (JWST) to observe an oddball gas giant exoplanet orbiting a dead star, a white dwarf, located some 80 light-years away. This "life after death" system gives scientists a portentous vision of what the solar system may look like in around 6 billion years after the sun has exhausted the hydrogen in its core, shed its outer layers, and left behind a smoldering white dwarf stellar remnant.

Prior to the final stages of that transformation, our star will have become a red giant, swelling out to many times its original radius, swallowing the inner rocky planets including Earth but leaving the outer planets  — although changing them irrevocably. Reflecting this, the white dwarf at the heart of this research is orbited by a Jupiter-sized exoplanet, designated WD 1856 b.

As WD 1856 b orbits its dead parent star, it crosses or "transits" the face of this white dwarf, known as WD 1856+534. By observing these transits with the JWST, the team was able to measure the mass and temperature of this Jupiter-like planet while also observing the composition of its atmosphere. To their surprise, they found WD 1856 b is hotter than expected. They also discovered how this planet came to have such an unusually tight orbit around its host white dwarf star.

"We're used to looking back in time when we use telescopes, but this is the first time we have been able to look forward to what might happen to the outer planets around the remnant of a sun-like star; it's like using a time machine to peer into the distant future of our solar system," team leader Ryan MacDonald from the University of St Andrews in Scotland said in a statement. "This is just the beginning of our exploration of planets orbiting dead stars with Webb, and the search for further planets orbiting white dwarfs is ongoing.

"Our results show that stellar death is not the end  — some planets experience a vibrant and lively future after the death of their star."

The team's research was published on Wednesday (July) in the journal Nature.

Survivor planet is a real oddball

The gas giant WD 1856 b was first discovered in 2020 by NASA's exoplanet-hunting spacecraft TESS (Transiting Exoplanet Survey Satellite) and the Spitzer Space Telescope. TESS detects exoplanets using the tiny dips in starlight they cause as they transit their host stars, blocking starlight.

This was the first intact planet ever discovered closely orbiting a white dwarf. What immediately stood out about WD 1856 b was how close its orbit is to its white dwarf host. The orbit is around 2% the size of Earth's orbit around the sun and takes just 1.4 Earth days to complete.

"The planet is quite the oddball. It's about the size of Jupiter, but the white dwarf it orbits is the size of Earth, so the planet is seven times larger than its star," MacDonald said.

The planet couldn't have always been in such a close orbit to its star. If it had, it would have been obliterated when the star transformed into a red giant before shedding its puffy outer layers and leaving behind a white dwarf.

"The big question is how WD 1856 b ended up where it is today, and there are two theories," team member Christopher O'Connor of Northwestern University said. "One is that the planet was swallowed by the host star as it was dying, and managed to survive on the inside. The other is that the migration took place due to the gravitational effect of other objects in the system. The white dwarf is part of a triple star system, and the outer companion stars could have influenced WD 1856 b's orbit."

The clue that allowed the team to differentiate between these migration mechanisms was the temperature of WD 1856 b, which at 260 degrees Fahrenheit (127 degrees Celsius) is about 240 degrees hotter than it would be if its only source of heat were the light from its white dwarf parent star.

With no energy available to warm the planet to these temperatures, the team reasoned that the temperature must be a residual effect of prior warming either from being engulfed by the red giant or during an inward migration. Using observations of the planet's mass of between four and 11 times that of Jupiter, the team was able to model how it would have cooled over time.

MacDonald and colleagues determined that WD 1856 b was likely heated up around 3 billion to 5.5 billion years ago. Its host star has been a white dwarf for longer than that, which means the exoplanet was safe during the star's destructive red giant phase, and moved into its tight orbit afterwards.

"As the planet moved inwards, its interactions with the strong gravity of the white dwarf will have caused it to warm up considerably, and it has been cooling ever since," O'Connor said.

The results indicate that Jupiter could move closer to the sun after the violent drama of its red giant phase and the destruction of the inner solar system. The findings also demonstrate the incredible observing power of the JWST and how the $10 billion space telescope is still discovering things no other instrument can.

"White dwarfs like WD 1856 are exceptionally dim compared to the planet-hosting stars we normally observe with the JWST," team member Victoria Boehm of Cornell University said.

"To make things even harder, the planet's transit only lasts 8 minutes, so it's very much if you blink you miss it! Capturing enough light to see WD 1856's spectrum, while also doing so quickly enough to not miss the transit, is something only Webb can do."

A huge, shining bauble of stars called Terzan 5 could be a clump of our galaxy's central bulge that hasn't been smoothed out into the mix, and has instead survived as a fossil relic leftover from the birth of the Milky Way galaxy.

"Terzan 5 may provide direct evidence that can help explain how bulges formed in galaxies throughout the universe," said Barbara Lanzoni of the University of Bologna in a statement. Lanzoni is a member of a team of astronomers, led by Bologna colleagues Giorgia Zullo and Francesco Ferraro, who tackled Terzan 5 with the James Webb Space Telescope (JWST).

Terzan 5 is a globular cluster — a huge sphere of stars with a total mass two million times greater than our sun's and a total luminosity 800,000 times greater. The problem is, Terzan 5 lies about 18,800 light-years away in the bulge of the Milky Way galaxy. This means dense lanes of intervening galactic dust block our view, significantly dimming Terzan 5's apparent brightness. That's why it wasn't discovered until 1968 by the Turkish–French–Armenian astronomer Agop Terzan.

Globular clusters tend to be ancient. They also tend to have formed all their stars in one giant burst. As such, all their stars should be the same age, 12 to 13 billion years old. Yet, a select few globular clusters show evidence of having more than one generation of stars. These include Omega Centauri, NGC 2808 and NGC 1783 in the Milky Way galaxy, as well as NGC 411 in the Small Magellanic Cloud and NGC 1696 in the Large Magellanic Cloud. Several explanations have been put forward, including the possibility that they are the core remnants of dwarf galaxies that have been stripped of most of their stars by gravitational tidal forces emanating from the Milky Way. Or perhaps these clusters were simply massive enough to retain some molecular gas for future stellar generations.

When the Hubble Space Telescope took a look at Terzan 5 in 2009 and then again in 2016, it found that it too was among the ranks of weird globular clusters with two generations of stars, dating back 12.5 and 4.7 billion years. However, because it is behind so much galactic dust, not even Hubble has the clearest of views.

The JWST, however, does. Its near-infrared vision can see through the dust.

"Webb's new near-infrared observations, cross-referenced with Hubble's archival observations, have given us a much clearer picture of the history of Terzan 5," said study leader Giorgia Zullo, who is a Ph.D. student at Bologna.

The JWST detected two further generations of stars, one generation born 3.8 billion years ago and another 2.5 billion years ago. Four generations of stars is hard to explain for any globular cluster, which is why the team think that Terzan 5 could be something more primordial: a leftover building block of the Milky Way's bulge that was never quite assimilated by our galaxy.

"For some reason, this peculiar clump of stars formed separately from the bulge and was not destroyed as the bulge itself formed," said Ferraro. "Terzan 5 is what we now call a bulge fossil fragment because it resembles the primordial clumps that contributed to the formation of the bulge."

Disk galaxies sport two main components: a relatively narrow disk formed from spiral arms, and a bulbous core called the bulge. Galactic bulges tend to be the oldest parts of galaxies, forming billions of years before the disks, at least in the Milky Way's case. The JWST is seeing this process occurring in the early universe, revealing clumpy, young galaxies, but given the great expanse of space and time that JWST is looking across, the observations of the building blocks that go into making these galaxies are still not totally clear. With Terzan 5, we could be looking at one of the building blocks of the Milky Way's bulge relatively close-up, and it could provide new insights into the birth of our galaxy.

Terzan 5 is probably not the only bulge fossil fragment either. As well as those other aforementioned globular clusters, some of which might be fossil fragments and others might be the cores of dwarf galaxies, the globular cluster Liller 1 close to the center of our galaxy shares many of Terzan 5's properties, including its high abundance of heavy elements produced by multiple generations of stars that have died either in supernova explosions.

The team are now looking to chase up another 40 or 50 globular clusters in the bulge to see if they could also be bulge fossil fragments, or whether they are just regular globular clusters.

The findings were presented at the 248th meeting of the American Astronomical Society in Pasadena, California which took place between June 14 and June 18. A paper describing the JWST observations has also been published in the journal Astronomy & Astrophysics.

Scientists have discovered that dying stars don't go down without a fight. New research suggests that when stars like the sun enter their red giant phase, they spit out blobs of plasma and receive a corresponding "kick" in the opposite direction.

Stars become red giants when the hydrogen in their cores is exhausted, and that core collapses. This results in the outer layers of the star where nuclear fusion is still occurring, puffing out and expanding the star's radius to as much as 100 times its original size. Those outer layers are eventually lost altogether, leaving behind a dense stellar remnant known as a white dwarf. The sun itself will undergo this transformation in around 5 billion years, swelling out to around the orbit of Mars and engulfing the inner rocky planets, including Earth.

California Institute of Technology researcher Jim Fuller calculated that before a star becomes a white dwarf, it will receive around 10,000 little kicks over the course of hundreds of thousands of years. The cause of these kicks is the ejection of blobs of plasma from the red giant stars.

"In this model, blobs of matter are chaotically being ejected from the surface of the bloated stars in an asymmetric fashion," Fuller said in a statement. "And every time that happens, the star gets a little kick in the opposite direction. Like Newton said, for every action there is an equal and opposite reaction."

The blobs of plasma will be chaotically ejected in random directions, but this will still result in an overall net push on the red giant, a phenomenon mathematicians call a "random walk." This is akin to randomly flipping a coin to decide whether to move north or south and still eventually finding yourself moved from your starting position.

Fuller determined that for a red giant, this random walk would see a movement in a random direction at a speed of around 2,200 mph (3,540 km/h). This may seem like a lot, but it pales in comparison to the kicks received by massive stars that explode as supernovas.

The lack of an explosion in the transformation of an average-sized star into a white dwarf makes these events less dramatic, but we have still seen evidence of this happening.

Caltech researcher Kareem El-Badry has previously discovered that widely separated binaries are less common in cases when one star has undergone the transformation into a white dwarf. One possible explanation is that repeated kicks during the red giant phase eventually break apart these loosely bound stellar pairs.

"If the orbital speed of the binaries is less than the kick speed, the wide binaries will become gravitationally unbound," Fuller said. Fuller's model also suggests something that astronomers are yet to see. He predicts that in some cases the kicks received by a red giant could send it pinballing toward a stellar companion, causing a massive explosion when the two collide.

Astronomers could now search the cosmos for such events, the discovery of which would help verify Fuller's model.

Fuller's results were presented at the 248th meeting of the American Astronomical Society in Pasadena. The study has been submitted to the Proceedings of the Astronomical Society of the Pacific.

Astronomers have a cosmic mystery on their hands, investigating a celestial crime scene to determine if a distant star has eaten a super-Earth exoplanet. The star may have had an accomplice — a failed star or "brown dwarf" companion — which may have steered the unfortunate planet toward its fiery doom.

The team charged with investigating this mystery first discovered hints of the crime when they found the star, TOI-5882, located around 1,300 light-years away, is surprisingly rich in the element lithium.

"You are what you eat, right?" team leader Brooke Kotten of the University of Michigan said in a statement. "We know that there's much more lithium in planetary material than there is in stars. So if a star eats a planet, it's going to take on a bunch of lithium."

So-called engulfment events such as this one occur very rapidly, on a timescale of a few days to a couple of weeks, which means catching stellar beings in the act of enjoying a planetary meal is extremely rare. Thus, astronomers have to act as cosmic crime scene investigators to reconstruct these events with the evidence at hand.

"That's what makes this field so exciting. You really are solving a mystery," Kotten said. "We can't just watch the crime happen, so we have to work with all the clues we're given to figure out whodunit."

One of the aims of these investigations is to discover the ways in which a star can devour a planet. One of the most common engulfment scenarios happens when a star runs out of hydrogen at its core at the end of its main sequence lifetime. This results in it swelling out to up to 100 times its original diameter, engulfing its attendant planets during its so-called red giant phase. This will occur in the solar system in around 5 billion years when the sun will puff out to around the orbit of Mars, swallowing the inner rocky planets, including our own.

However, Kotten and colleagues know this isn't what has happened in the TOI-5882 system, as this star hasn't yet become a red giant. Instead, the researchers think the sun-like star had assistance from its brown dwarf companion.

Companion brown dwarf of partner in crime?

Brown dwarfs get their slightly unfortunate nickname of "failed stars" because, despite forming from collapsing clouds of gas and dust, just like stars, they fail to grow to the masses needed to trigger the nuclear fusion of hydrogen to helium in their cores, the process that defines what a main-sequence star is. They're quite mysterious by existing in this sort of limbo between planet and star.

This particular brown dwarf has around 20 times the mass of Jupiter, or around 2% of the mass of the sun. That's not massive enough to trigger nuclear fusion, but is massive enough for it to have enough of a gravitational influence over planets orbiting TOI-5882. That means the team suspects this brown dwarf could have perturbed the orbit of this unfortunate planet enough to send it plummeting into its star.

This is something the scientists will need to investigate further. They may not have enough information yet to determine this planet's cause of death, but they do have some evidence that helps them identify the kind of world it would have been before it was obliterated. This comes from observations of the chemical composition and lithium content of 62 stars with similar ages and masses to TOI-5882.

"Lithium atoms delivered by planetary engulfment to a star are like sports fans arriving at a stadium," team member Seth Jacobson of Michigan State University said. "There may already be a few early arriving fans present, representing the initial amount of lithium in the stellar atmosphere, but they are quickly outnumbered."

From the lithium abundance they measured, the team has determined that this planet was a so-called super-Earth with a mass somewhere between two times that of our planet and the mass of the solar-system ice giant Neptune, which is around 18 times as massive as Earth.

"The fact that we can look at a star 1,300 light-years away and say with confidence, 'This star has more lithium than you would expect,' is a testament to both the precision of modern instrumentation and the hard interpretive work that goes into making sense of that signal," said Melinda Soares-Furtado, a senior author of the study and assistant professor at the University of Wisconsin. "And it's not like you have to cherry-pick the data to make it stand out. It's robust. No matter how you slice it, TOI-5882 is so enriched in lithium it shows up as being at least in the 97th percentile."

Soares-Furtado added that TOI-5882 is one of the few stars she has seen demonstrating evidence of planetary engulfment, although a few of the other stars in the control sample were enriched in lithium, albeit not to the extent of TOI-5882. That leaves another mystery for the team to solve, something that Soares-Furtado may well be quite content with.

"When I was growing up, I dreamed about becoming a private investigator," she said. "I think that explains a lot about where I ended up. I do feel like a detective."

The team's research was published on Monday (June 15) in The Astrophysical Journal.

Astronomers have discovered chemical differences between binary stars that indicate one is a cosmic cannibal that has devoured at least one planet.

Binary stars should have the same chemical composition because each star is formed from the same vast cloud of gas and dust; however earlier this year the team behind this new research discovered that the two stars of HD 81809, located around 101 light-years away, are chemically different. One of the stars, HD 81809B, has a much greater concentration of elements heavier than hydrogen and helium, which astronomers call "metals," at its surface than its binary partner HD 81809A.

This new research suggests that the reason for the metal enrichment of HD 81809B is that this star has consumed an exoplanet which was between 50 and 75 times the size of Earth.

"This is the first binary system to be found with this chemical difference, which is very unusual," team leader Nuno Moedas of the Technical University of Denmark told Space.com. "Binary systems are 'like siblings' in that they are born from the same molecular cloud, meaning they have the same chemical composition. As with siblings, some differences in element abundances can appear due to physical processes. However, these differences will be much smaller than those of HD 81809."

Moedas added that there are only two possible explanations for the differences between HD 81809B and HD 81809A.

"One is that the stars are not 'real siblings' and were born from different molecular clouds containing different elements," Moedas said. "The other explanation is that star HD 81809B suffered a more drastic event during its evolution, such as ingesting a planet, which could have changed its chemical composition."

There is a "smoking gun" piece of evidence that planetary engulfment is the correct explanation for the metal enrichment of HD 81809B, however.

"It could be very hard to distinguish the two scenarios, but the main evidence for a planet's engulfment is the high abundance of lithium in HD 81809B that is not normal," Moedas said. "Lithium is a very volatile element, and it is easily destroyed in stars, so we expect very low abundances of this element when observing stars. For the case of HD 81809B, the most viable explanation for the large presence of lithium is an ingestion of a planet."

The team isn't quite sure how HD 81809B came to feast on one of its planets, but Moedas suggests it could be the result of gravitational interactions between the binary stars disrupting the orbit of the unfortunate planet, resulting in it falling into one of its stars. The question also remains of how many planets HD 81809B has devoured.

"We can only estimate the amount of planetary material required, which we find to be 75 times the mass of Earth. It is possible that the star ingested three planets, each 25 times more massive than Earth," Moedas said. "The event happened a few million years ago, and there are physical processes in the star that will 'clean up' the evidence and try to make the star's chemical abundance similar to that before the event."

Because of the physical processes within HD 81809B, the team can't tell much more about the planet, or planets that were devoured. However, there is a possibility that this information may be recovered from a dusty disk of debris detected in this system.

"We still do not know the exact location, but if it is around the secondary star, it could be the remains of a planet falling into the star," Moedas said. "We could use this to understand the composition of the planet. However, we are far from being able to study this debris disk with the current instruments we have. We probably still need to revisit this system, as there is still a lot we don't know.

"There is a lot to discover."A pre-peer-reviewed version of the team's research appears on the paper repository site arXiv.

NASA's Chandra X-ray spacecraft has detected the supernova wreckage of a dead star near the supermassive black hole that sits at the heart of the Milky Way, around 26,000 light-years from Earth.

The team behind the discovery believes the star that died to create this wreckage erupted around 1,700 years ago. This represents the closest supernova debris found to our central supermassive black hole, Sagittarius A* (Sgr A*).

The supernova wreckage sits within a bubble of ionized hydrogen gas, which is a bright source of radio waves, and has been dubbed Sagittarius C (Sgr C). The wreckage was detected by Chandra and the XMM-Newton X-ray space telescope as a "blob" of X-rays. The shell of ejected material appears to be moving at a staggering 2 million miles per hour (3.2 million kilometers per hour).

Supernova wreckage like this is important for the chemical enrichment of galaxies, including the next generation of stars and planets.

That's because when massive stars like the progenitor star of this debris explode, the heavy elements they have forged from hydrogen and helium are jettisoned into their surroundings.

Eventually, these elements mix with surrounding clouds of interstellar gas and dust. Later, cool and dense regions in these molecular clouds collapse under their own gravity, forming new stars. The envelopes of material around these infant stars eventually form clumps that gather more and more mass to become planets.

There is still some ambiguity surrounding this wreckage, however. The team behind the observation didn't find increased amounts of the elements that would have been blasted out by the exploding star.

This could be because this debris has already mixed with the surrounding gas and dust. Alternatively, it could suggest this X-ray blob isn't the result of a supernova explosion at all, but rather comes from gas heated by the hot massive stars in this region of the Milky Way.

The team behind this research doesn't consider this explanation likely. That is because this X-ray emission is around ten times brighter than the typical emissions from clusters of hot massive young stars.

The team's research was published in The Astrophysical Journal.

One of the pleasures of stargazing is noticing and enjoying the various colors that stars display in dark skies.

Star colors are always interesting to observe, since they add so much to the character of the constellations. These hues offer direct visual evidence of how stellar temperatures vary. A good many of the luminaries of the summer season — such as brilliant Vega, which stands about halfway up in the east-northeast sky as darkness falls — are bluish white. Still, we can easily find other, contrasting colors there as well. Look at the reddish Antares and the yellowish-white Altair. And at the top of the line of this summer's retinue, brilliant orange Arcturus holds forth in solitary splendor high toward the south.

Even as you observe these stellar colors, do you notice that they're recognizable only for the brightest stars? This is due to the physiology of the eye, more specifically, the fact that the color sensors on the retina — the cones — are insensitive to faint light. Under dim illumination, the retinal rods take over. But their greater light sensitivity is offset by their color blindness. This is why faint stars tend to appear white to our eyes. However, if we look at them through a binocular or a telescope, their amplified brightness stimulates the cones, which detect their color.

Colors by contrast

One of the best ways to see star colors is by contrast. Let's return to Arcturus for a moment. The classic procedure for locating this star is to follow the arc of the Big Dipper's handle southeastward. Back in the 1950s, a very popular lecturer at New York's Hayden Planetarium was Henry M. Neely (1879-1963), who had a favorite ditty for locating Arcturus and another bright star of late spring/early summer: "Follow the arc to Arcturus and speed to Spica."

Spica shines with a distinct bluish tint. Move your eye rapidly back and forth between Arcturus and Spica to see the great difference in their respective orange and blue hues.

Another very effective procedure is to observe a double star with contrasting tints.

Probably the most colorful double star in the night sky can be found about halfway up in the eastern sky at 11:30 p.m. local daylight time: Albireo in the constellation of Cygnus the Swan, also known as the Northern Cross. Albireo supposedly marks the swan's beak.

A small telescope or even a pair of steadily held binoculars will readily split Albireo into two tiny points of light of beautiful contrasting colors: the brighter one a rich yellowish orange, the other a deep azure blue, both placed very close together. A stunning view will come with a telescope magnifying between 18x and 30x.

Stars hot and cool

Earlier, we referred to Antares as being reddish, which is how it's always described. But actually, that isn't correct. What we regard as "red" stars (which are catalogued as spectral class M) are really yellow-orange and approximately the same color as an old-fashioned incandescent light bulb. Both it and M stars have about the same 3,000 Kelvin color temperature.

Our eyes evolved to take advantage of the radiation emitted by the sun, which is an average star as far as temperature and color are concerned. Very hot and cool stars, on the other hand, are strongest in the ultraviolet and infrared ranges, respectively.

Starlight is similar to what physicists call black-body radiation — the electromagnetic waves given off by a body that emits and absorbs radiation 100% efficiently. (Anything that truly absorbed all the light falling on it would be black, hence the name). We know that the hotter a star, the more energy it emits at every wavelength — for very hot stars, the peak emissions are directed toward the shorter (bluer) wavelengths.

Simply put, the location of the peak emissions determines the star's color. We can break this all down into two rather simple laws that are immediate consequences of blackbody radiation.

For an object at a particular temperature, the total energy radiated at all wavelengths is given by the Stefan-Boltzmann law, after its two discoverers, Josef Stefan (1835-1893) and Ludwig Boltzmann (1844-1906). The Stefan-Boltzmann law states that the rate at which an object radiates heat is proportional to the fourth power of the absolute temperature, expressed in degrees Kelvin. Thus, if the temperature doubles, the energy output increases 16 times. If it triples, the output increases 81 times.

The second law is called Wien's law, named for Wilhelm Wien (1864-1928). It states that the wavelength of a star's peak output is inversely proportional to the temperature. If the temperature doubles, the peak wavelength is halved. Wien's law has a very colorful consequence, which can be demonstrated by the coils on an electric stove. As their temperature increases, we first feel infrared radiation, then see it glowing dull red, followed by bright red and still brighter orange. If it could continue heating without melting, the coils would turn yellow, white, then blue-white while becoming extremely brilliant — just like stars.

So, the color is determined by Wien's law, while the total radiation (both visible and invisible) is determined by the Stefan-Boltzmann law.

If you're looking for a telescope to get a closer look at the night sky our best telescopes for deep space guide may help. We also have a guide to astrophotography for beginners, which covers everything from equipment to shooting modes and more.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope, The Old Farmer's Almanac and other publications.

A gorgeous new portrait of an ancient star cluster reveals an unexpected imperfection: a visible gap in the brightness of its stars.

The stunning image, taken by the European Space Agency’s (ESA) Euclid space telescope, captures NGC 6397 — one of the closest globular clusters to Earth. NGC 6397 is a glittering swarm of hundreds of thousands of stars packed tightly together, but when astronomers took a closer look, they discovered something unusual hidden within the sparkles.

A graph plotting the stars by their brightness and color revealed a conspicuous gap — a narrow region where certain stars should have appeared but didn't. The feature is so distinct that it stands out visibly in the data, appearing almost like a blemish in an otherwise smooth distribution of stars, according to a statement from the Space Telescope Science Institute (STScI).

The discovery emerged from observations collected by Euclid, which is primarily tasked with investigating dark matter and dark energy. Initially, the team was studying the motions of stars within the globular cluster using data from both Euclid and the Hubble Space Telescope. When analyzing the data from NGC 6397, the researchers weren't searching for missing stars. Instead, they stumbled across the feature while studying the cluster's stellar population.

"The discovery was serendipitous," Andrea Bellini, one of the research paper's primary authors from STScI, said in the statement. "We were not looking for the gap, but we found it."

The gap occurs among red dwarf stars, the most common type of star in the Milky Way. Researchers believe the visible void is linked to changes deep within the stars as they transition from having partially convective interiors to becoming fully convective. That shift slightly alters the stars' structure and luminosity, leaving relatively few stars at certain brightness levels.

The idea that stellar populations can contain small “missing” ranges of stars first emerged in 2018, when ESA’s Gaia mission revealed a subtle gap in the brightness distribution of hundreds of thousands of nearby stars. Plotted on a Hertzsprung–Russell (HR) diagram, the data suggested that even in large stellar populations, stars do not always fall into perfectly smooth patterns.

The new Euclid observations build on that idea by identifying a similar feature inside the globular cluster NGC 6397, which is a tightly packed, roughly spherical collection of stars bound together by gravity, often found in the outskirts of galaxies and containing some of the oldest known stars. Using a HR diagram, the team again mapped stars by their luminosity and color and discovered a narrow shortage of red dwarfs at specific brightness levels.

Because relatively few stars pass through this brief transitional stage in their evolution, there is a corresponding dip in their numbers at those luminosities. On the HR diagram, that shortage appears as a thin gap cutting through the otherwise continuous band of stars.

"Globular clusters are the ideal laboratories to study stellar evolution and stellar populations," Massimo Griggio, lead author of the study from STSc, said in the statement.

The precise brightness where the gap appears, along with the properties of the stars involved, helps astronomers estimate how far away the cluster is. NGC 6397, an ancient globular cluster about 13.4 billion years old, lies roughly 8,000 light-years away in the constellation Ara, the researchers said.

This marks the first time astronomers have identified the phenomenon in a globular cluster, providing a new opportunity to test models of stellar evolution using one of the galaxy's oldest and most densely populated stellar systems.

Their findings were published May 12 in the journal Astronomy & Astrophysics.

A triple star system in which the stars all eclipse one another from our vantage point is standing out as one of the best studied stellar trios; as the stars age, they could even merge.

The triple system, known as TIC 295741342, is 3,080 light-years from Earth and was found by NASA's TESS (Transiting Exoplanet Survey Satellite) mission. It features a binary system composed of two stars almost identical to the sun, orbited by a larger third star of 1.7 solar masses.

Triple star systems abound in the galaxy, but what makes TIC 295741342 more remarkable is that all three stars orbit each other in the same plane, and that plane is aligned edge-on to us.

TESS charts the light curves of stars, which is essentially a graph of brightness versus time. Typically, it is looking for the small dip in light as an exoplanet moves in front of, or transits, its star, but TESS also excels at witnessing stars in binary and triple systems also moving in front of each other — not just transiting, but eclipsing.

The light curve for TIC 295741342 is described by Brian Powell, who is an astronomer at NASA's Goddard Space Flight Center, as having a "head-and-shoulders" pattern, especially when inverted. TESS detects a dip in light as the stars of the binary at the heart of the TIC 295741342 eclipse one another. This dip is one of the "shoulders." Then, TESS detects another, deeper dip in light as the third, outermost star moves in front of the binary and eclipses both its stars, creating the "head."As the binary moves out from behind the third star while still eclipsing each other the light curve steps back up to the initial dip in light – the other "shoulder" — and finally back to full brightness when no stars are in eclipse.

Powell told Space.com that "very few known triple star systems are so near-perfectly coplanar as TIC 295741342, especially for being such a wide system."

Disk fragmentation

By coplanar, Powell means that all three stars orbit in the same plane, just as the planets of the solar system orbit in more or less the same ecliptic plane. Our planets are found in the same plane (or more specifically, within six degrees of it) because they formed from a disk of gas and dust that ringed the young sun. Powell suspects the stars of TIC 295741342 also formed from a disk, but one that fragmented.

"The protostellar disk broke into pieces to form stellar companions," said Powell.

Not all triple systems form this way. In many cases, the third star orbits at an angle to the central binary — but in those scenarios, the third star was gravitationally captured by the binary while they were all still in the close confines of their birth cluster.

Disk fragmentation is not a rare phenomenon, however. Hundreds of coplanar triple systems have been found, their numbers enhanced in particular by the discoveries made first by NASA's Kepler Space Telescope and now TESS. Yet few triple star systems are as well studied as TIC 295741342.

The two sun-like stars that make up its binary component have an orbital period of just 4.75 days. Separated by a distance of about 6.61 million miles (10.6 million kilometers); their masses were deduced from radial velocity measurements by the spectrograph on the 1.5-meter Tillinghast reflector at Whipple Observatory in Arizona. The third, outer star takes 412.8 days (1.13 years) to orbit the binary pair, at a distance of 157.7 million miles (253.7 million kilometers).

This is considerably wider than many other triple eclipsing stars that have been found, such as Lambda Tauri, which was identified in 1956 as the first known eclipsing triple where the outermost star has a 30.5-day period. Even closer is TIC 290061484, an eclipsing triple found by TESS in 2024, where the central binary has a period of 1.8 days and the outer star has a period of only 24.5 days.

Dangerous ground for planets

Could such triple systems harbor planets? There's an exclusion zone for planets in circumstellar orbits around binary stars in which a planet can get no closer than four times the binary period. In the case of the inner binary in TIC 295741342, that would result in a zone of instability out to an orbital period of 19 days, which is still pretty close to the binary stars. However, the presence of the outer third star at just a little further than the distance of Mars from the sun will curtail many possible planetary orbits further out from the binary. The third star could have its own planets, but again the binary would make any on larger orbits unstable.

However, in wide triple systems it's possible there could be stable planetary orbits, with some caveats.

"The orbit of a planet would have to be very wide," said Powell. "And it would be difficult to find."

One of the widest eclipsing triple systems is TIC 99013269, where the outer star is on a 604-day orbit at a distance of about 230 million miles (370 million kilometers) — less than half the distance of Jupiter from our sun.

It's fun to speculate about what inhabitants of any worlds or moons that exist around an outer star would experience during the eclipses. Picture a world with a habitable moon, tidally locked to its planet. For most of the time it will be in some form of daylight, whether from its star, which is the outermost star, or from the binary star a little further away, or even reflected light from the planet. However, at certain times a series of eclipses will line up — the outer star will eclipse the binary star, and the planet will eclipse the outer star as seen from the moon.

It would only be on these occasions when the planet-facing hemisphere of the moon would be in total darkness.

A future nova

While the coplanar nature of TIC 295741342 tells us about its beginnings, what we have learned about the stars thanks to them being coplanar is also telling us about how they will end.

The outer star in the TIC 295741342 system is beginning to age. It has moved off from the main sequence of hydrogen-burning sun-like stars and has turned into a red giant. It has already swollen to a diameter 10.6 times larger than our sun, and it will continue to expand. Eventually, it will grow so large and diffuse that the gravity of the binary star will begin to steal matter away from the red giant, which could lead to all manner of shenanigans.

Its diffuse outer layers may form a common envelope of stellar material encapsulating all three stars. This could cause the binary's orbit to become unstable and potentially merge. Then in the future, when the binary star component enters the red giant phase, long after the outer star has become a compact white dwarf, the mass transfer could begin again in the opposite direction, with matter falling onto the surface of the white dwarf. This would trigger explosive outbursts on the white dwarf, which would be seen across the galaxy as a nova eruption.

So its seems that the story of the three stars of TIC 295741342 has already been written, thanks to the careful observations including four years of radial velocity studies to calculate the mass of the planets, the observations of the eclipses by TESS, and the determination of the shape of the orbit of the outer star.

"The value in this system is the comprehensive data," said Powell. "This makes the system an excellent candidate for evolutionary studies."

The observations of TIC 295741342 are described in a paper currently on the pre-print archive arXiv.

The clashing magnetic fields of a white dwarf star and its neighboring red dwarf star are the source of signals from space that have remained a puzzle for over 20 years, radio astronomers in Australia have found.

The signals, or long-period radio transients, are a class of celestial radio emissions discovered in 2005. Most radio-producing objects release bursts that last for mere seconds or less, but long-period radio transients, about a dozen of which are known, produce radio waves in bursts lasting from minutes to over an hour.

Speculation had focused on highly magnetic pulsars called magnetars as the origin of these radio bursts, but now new research led by Kovi Rose of the University of Sydney, using the Australian SKA Pathfinder (ASKAP) radio telescope, has shown that symbiotic binaries are to blame for at least some long-period radio transients.

Symbiotic binaries feature a compact object — usually a white dwarf, which is the core remains of a sun-like star — stealing matter from a close companion star. This scenario often leads to a nova explosion when too much material accretes onto the surface of the white dwarf.

"Long-period radio transients have puzzled astronomers for years," said Rose, who is a postgrad student, in a statement. "Now we've been able to show that the source for one of these transients comes from a white dwarf actively pulling material from a companion star."

The system in question has been catalogued as ASKAP J1745-5051, and features a white dwarf that is about the diameter of Earth but a mass similar to that of our sun, accreting matter from a red dwarf star with a mass just a tenth of our sun's mass.

What makes ASKAP J1745-5051 stand out is that not only does it produce these long-period radio bursts, but it also produces blasts of X-rays.

"These emissions are all tied to the orbital motion of the system," said Rose. "But interestingly, the radio and X-ray signals don't peak at the same time, which tells us they're being produced in different regions of the system."

The X-rays are produced as matter spirals in from the red dwarf onto the white dwarf. As it gets closer to the white dwarf, gravity causes it to bunch up, friction increasing the temperature to hundreds of thousands, or even millions, of degrees, which is hot enough to emit X-rays. Exactly where it bunches depends on the relative positions of the white dwarf and red dwarf.

The origin of the radio waves is more complex. Both the white dwarf and the red dwarf have their own intrinsic magnetic fields. Their orbit around each other, which takes just 1.4 hours to complete, is not circular but strongly elliptical, meaning that at times the two objects are closer together than at other times. When they are close their magnetic fields clash, stripping charged particles from each other's surface. These charged particles then spiral around the magnetic-field lines and release a form of radio waves known as synchrotron radiation. The radio bursts last for the duration that the magnetic fields are in contact, every 1.4 hours.

While this explains ASKAP J1745-5051, it does not necessarily explain all long-period radio transients. For instance, only one other has been shown to produce X-rays. It is therefore possible that some other long-period radio transients have a different origin. However, Rose hopes that this new research will help distinguish between the different types.

"This system gives us a way to decode these signals," he said. "It could help us determine whether other long-period transients are more like pulsars or like white dwarf systems, acting like a stellar Rosetta Stone."

The findings were published on June 1 in the journal Nature Astronomy.

Some of the galaxy's most spectacular stellar nurseries resemble giant cosmic wagon wheels, with spoke-like structures that scientists say were sculpted by shockwaves from stellar explosions and powerful stellar winds.

Using powerful 3D simulations, researchers from Kyushu University and Nagoya University in Japan found that shockwaves racing through giant clouds of gas can carve out the spoke-like filaments often seen surrounding newborn stars. The findings could help explain the origin of so-called hub-filament systems — sprawling star-forming regions where long streams of gas radiate toward a dense central hub, creating a pattern that resembles the spokes of a wheel, according to a statement from Kyushu University.

"Stars are born inside molecular clouds — vast, cold clouds of gas that drift through space," Shingo Nozaki, lead author of the study, said in the statement. "But they only form in the coldest and densest parts of those stellar nurseries, where gas can collapse under its own gravity. In some of these star-forming regions, gas is organized into characteristic hub-and-spoke patterns known as Hub-Filament Systems (HFS)."

Astronomers have observed these structures throughout the Milky Way, but exactly how they form has remained an open question. The team used advanced 3D magnetohydrodynamic simulations to recreate the process, revealing that shockwaves propagating through giant molecular clouds can naturally generate the striking wheel-like architecture seen in some of the galaxy's most active stellar nurseries, according to the study.

Many stellar nurseries contain narrow filaments that funnel material inward toward crowded central regions where stars are actively forming. Understanding how those filaments emerge is key to understanding how gas accumulates and ultimately collapses into new stars.

For the study, the researchers built a virtual molecular cloud threaded with magnetic fields and ran the simulations on ATERUI III, a supercomputer dedicated to astronomical research. Gravity first was seen pulling the magnetic fields inward, creating an hourglass-shaped configuration. The team then blasted the cloud with a simulated interstellar shockwave similar to those generated by expanding supernova remnants or powerful winds from massive stars. The result was a remarkably realistic hub-filament system.

As the shockwave swept through the cloud, it encountered different parts of the curved magnetic field at varying angles, creating oblique shocks that amplified sections of the field and established preferred pathways for gas to flow. Over time, these channels funneled material into elongated filaments stretching toward a central hub, producing the spoke-like structure seen in telescope observations.

The simulations also tracked how matter moves through stellar cradles. Dense gas tends to flow along the filaments, accelerating as it approaches the hub, while lower-density material between the spokes remains comparatively still. The researchers say this behavior may help explain why only a small fraction of gas in molecular clouds ultimately forms stars, according to the statement.

Modeling the interplay between gravity, magnetic fields and shockwaves over millions of years, allows researchers to study processes that are otherwise difficult to observe directly. Future work will test a broader range of cloud structures and shockwave conditions, which could clarify why hub-filament systems vary across the Milky Way and offer new insight into the formation of massive stars and stellar clusters. The results also point to a broader cosmic cycle of destruction and creation, in which shockwaves from dying stars help shape the environments where new stars are born.

Their findings were published March 18 in The Astrophysical Journal Letters.

Astronomers have discovered the first signs that tiny red dwarf stars can devour their own planets.

Scientists had previously suspected that red dwarfs, which are considerably smaller and dimmer than the sun, could consume their own planetary systems — but evidence has been elusive. Until now, that is.

Researchers have used data from the Gaia-ESO Spectroscopic (GES) survey to discover red dwarfs with a high lithium content. This is unexpected, as red dwarfs shouldn't contain any lithium at all — unless they have gathered it by feasting on their home planets.

"Because these low-mass stars should have depleted all their lithium, the addition of even a trace from their forming planetary systems is readily seen — like throwing paint onto a completely blank canvas," team leader Robin Jeffries from Keele University said in a statement.

Though red dwarfs only possess between 8% and 60% of the mass of the sun, and are thus much cooler than our star, they are believed to harbor incredibly hot and violent interiors. This means any lithium they are born with should be rapidly burned through during the nuclear fusion processes that provide the star with energy to radiate.

This means stellar scientists have long been aware that discovering lithium in the atmospheres of these cool, dim stars would indicate they had consumed planets still rich in lithium from their initial creation. Indeed, this team found six red dwarfs in three different star clusters with vastly more lithium than would be expected.

The scientists analyzed their data further, determining that the red dwarf stars may have consumed the equivalent of three to ten Earths in planetary matter in total. This destructive process caused an influx of lithium into their atmospheres.

The fact that red dwarfs are the most common type of star in the Milky Way, accounting for around 75% of the stars in our galaxy, means this type of planetary engulfment may be extremely common.

Future research into these planet-eating red dwarfs could reveal at what stages of their existence they are more likely to consume their poor worlds, giving scientists a clearer picture of the early lives of planetary systems.

The team's research was published on Thursday (May 28) in the journal Monthly Notices of the Astronomical Society.

NASA's Fermi Gamma-ray spacecraft has observed a super-bright, supercharged supernova explosion that may have been powered up by a highly magnetic dead star, a type of neutron star called a magnetar. This magnetar would have actually been born in the supernova itself, forced into existence when the core of a star that was much more massive than the sun underwent gravitational collapse at the end of its life.

During these core-collapse supernovas, stellar cores with between one and two times the mass of the sun crush down to a radius of around 12 miles (20 kilometers) to create a neutron star, just like scientists say they see here. Not only does this rapid compression mean that neutron stars are made of material so dense that one teaspoon of it brought to Earth would weigh around 10 million tons (think 350 Statues of Liberty sitting on a teaspoon), but it also causes them to spin at rates as rapid as 700 times every second. The magnetic field lines of these dead stars are also forced together, intensifying the strength of neutron stars' magnetic fields, which makes magnetars the most powerful magnetic objects in the known universe.

"For nearly 20 years, astronomers have searched Fermi data for gamma-ray signals from thousands of supernovae, and while a few intriguing hints have been reported, none were definitive until now," team leader Fabio Acero of the University of Paris-Saclay said in a statement.

A superbright supernova

Over the last few decades, astronomers have observed around 400 core collapse supernovas, which, depending on the initial mass of the dying star involved, can also birth a black hole. Some of these stellar explosions are described as "superluminous" because they produce in excess of 10 times as much visible light as other core-collapse supernovas.

In 2024, scientists revealed they had successfully used Fermi to spot gamma-rays, the most energetic form of light, emitted from a supercharged supernova designated SN 2017egm. This supernova erupted around 440 million light-years away in the galaxy NGC 3191. Though that distance is so vast it took gamma-rays from the event 440 million years to reach Earth and Fermi, it is still one of the closest core-collapse supernovas to Earth ever seen.

"We searched for gamma rays from the six nearest superluminous supernovas seen during the first 16 years of Fermi's mission," Guillem Martí-Devesa, of the Institute of Space Sciences in Barcelona, Spain, said in the statement. "Only SN 2017egm shows evidence for gamma rays, confirming earlier hints that some supernovas can be as luminous in gamma rays as they are in visible light. This opens up a new window for studying these fascinating events."

Scientists are keen to discover what it is about superluminous supernovas that lets them pack such a powerful punch. One theory suggests this extra energy comes from the fact that these events birth a magnetar with magnetic fields 1,000 times stronger than those of "ordinary" neutron stars.

This team observed the optical and gamma-ray radiation emitted by SN 2017egm and compared this data to theoretical models of the flow of light and particles from a newborn magnetar. The models specifically reproduced how said particles would interact with the expanding shell of material shrugged off by the supernova's dying progenitor star. Of particular interest was a cloud of electrons and positrons in addition to their antimatter counterpart particles.

Scientists believe those particles were thrown out by the rapidly spinning newborn magnetar and call the cloud a magnetar wind nebula. The magnetar wind nebula is believed to boost the production and absorption of gamma-rays. One of the processes that would allow it to do this is the annihilation of particles and the release of energy as gamma-rays that occurs when a matter particle and its antimatter counterpart meet. These gamma-rays strike the outer shell of supernova debris and are turned into lower-energy optical light, explaining why these superluminous supernovas are so bright in visible light.

"About three months after the collapse, as the supernova debris expands and cools, the gamma rays can begin to leak out," Acero said. "This magnetar model best reproduces the supernova's luminosity and the arrival time of its gamma rays during the first months, but we see room for improvement at later times, when the visible light fades quite irregularly."

Acero and colleagues have a theory of what may be causing this gradual fade-out, suggesting it could be the result of debris ejected by the destroyed star hundreds of years prior to its supernova destruction falling back onto the magnetar.

The team also had one eye on the future, assessing how efficient the new ground-based gamma-ray observatory, the Cerenkov Telescope Array Observatory, will be at spotting events like SN 2017egm. They found that in 50 hours of observing time, the telescope array, located at the Paranal Observatory and on the island of La Palma, Spain, should be able to spot similar cosmic blasts up to a distance of around 500 million light-years.

That could help scientists finally understand these super-powerful supernovas.

"The magnetar central engine mechanism discussed in this paper builds upon a lot of observational and theoretical advances in magnetars over the last 20 years," team member Judy Racusin, at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said. "Observing gamma rays from supernovae will give us a new way to explore their inner workings."

The team's results were published on Wednesday (May 20) in the journal Astronomy & Astrophysics.

Skywatchers across parts of the Pacific will see the moon pass in front of the bright star Regulus on May 23, temporarily blocking its light in a celestial event known as a lunar occultation. Elsewhere, viewers will watch the star pass extremely close to the lunar disk as the pair drift through the constellation Leo.

Why can't everyone see the moon occult Regulus?

The moon orbits Earth at an average distance of just 238,855 miles (384,400 kilometers), close enough for an effect called "parallax viewing" to occur, where an object appears to be in a subtly different position against its backdrop based on where you view it from. The parallax effect can cause the moon's position to vary by as much as 2 degrees depending on where you are on Earth, according to NASA.

Who will see the moon occult Regulus?

Stargazers in Fiji, Samoa, Tonga and a host of other Pacific island nations will see the shadowed side of the half-lit moon pass in front of Regulus during the early hours of May 23, blocking its light entirely, according to the astronomy guide In-The-Sky.

From Sydney, Australia, the blue-white light of Regulus will appear to graze the top of the lunar disk after sunset, before skirting around its sunlit side to set beneath the moon shortly before midnight.

U.S. viewers will get their best view of the cosmic duo overnight on May 22-23, as the moon advances towards Regulus through the late-spring sky. The moon and Regulus will be separated by roughly 1 degree, about the width of your little finger held at arm's length, by the time they set on the western horizon in the early hours of May 23, though the occultation itself won't be visible.

Don't forget, you can simulate exactly what the occultation will look like from your location by using a smartphone astronomy app, such as Stellarium or Sky Safari 7 Pro.

Editor's Note: If you capture an image of the moon with Regulus and want to share it with Space.com's readers, then please send your photo(s), comments, and your name and location to spacephotos@space.com.

NASA's Artemis 2 astronauts had quite the view on their "roadtrip" to the moon.

In this image, captured by the astronauts onboard the mission's Orion capsule "Integrity," you can see the swirling stars of space from the window as the crew journeyed from our home planet to the moon.

What is it?

This past April, four astronauts — commander Reid Wiseman, pilot Victor Glover and mission specialist Christina Koch of NASA and Canadian Space Agency mission specialist Jeremy Hansen — blasted off on a 10-day journey around the moon and back as part of NASA's Artemis 2 mission.

The quartet flew in an Orion capsule that they named "Integrity." This spacecraft came equipped with four windows, enough for each astronaut to have his or her own view. And you can see in this image that through these windows, the astronauts could watch the stars swirling by on their cosmic journey.

The crew successfully splashed down back on Earth in the Pacific Ocean on April 10. If all goes to plan, Artemis 2 will be followed by the Artemis 3 docking test in Earth orbit in 2027 before Artemis 4 lands humans on the moon in late 2028.

Why is it incredible?

On roadtrips on Earth, it's always fun to look out the window and watch the world pass you by. But on this journey, the view out the window was out of this world — literally.

This roadtrip snapshot also signifies something bigger: a big step forward in the journey back to the moon with Artemis. NASA's Artemis program aims to return humans to the lunar surface for the first time in over 50 years, since the agency's final Apollo mission in 1972.

But the plan isn't just to go back for a singular, celebratory landing on the lunar surface. Instead, NASA is aiming for a longer-term presence on the moon. Who knows? Future astronauts could soon be looking out their windows at the view on their way to stay at a moon base.

In its infancy, the universe had a bit of an identity crisis.

For the first few hundred million years, the vast cosmic gas between galaxies was primarily a chilly, dense affair. But then, it seemed to wake up, deciding to get all warm and fuzzy.

This strange shift in the cosmos’ early disposition is a crucial clue to how the very first galaxies burst into being, shaping everything we see today. The early universe, a mere whisper after the Big Bang, just a few hundred million years old — that's when the first stars and galaxies were starting to flicker on, like fairy lights across a cosmic dark.

The fuel for all this grand production: gigantic clouds of gas, mostly hydrogen. Astronomers have always suspected these baby galaxies were busy, but new glimpses from the James Webb Space Telescope are showing them to be even brighter and larger than our wildest dreams. They're like finding teenagers sitting in a kindergarten class, way ahead of their expected development.

This cosmic precociousness means our existing models of how galaxies form might need a serious tune-up. We thought we had a pretty good handle on how gas falls into dark matter halos, cools down, and then ignites into stars. But the JWST data suggests a much more aggressive, faster-paced star-making frenzy in those early days. The question becomes: How did these young galaxies manage such a booming business so quickly?

To untangle this mystery, Umberto Maio from the INAF-Italian National Institute of Astrophysics and the Institute for Fundamental Physics of the Universe, working with Céline Péroux at the European Southern Observatory, decided to dive into the virtual cosmos. They created incredibly detailed computer simulations, a sort of cosmic time machine called ColdSIM, to rewind the clock and watch how gas behaved in the first billion years after the Big Bang. Their goal was to make predictions about the early universe’s baryon budget — that's the accounting sheet for all the "normal" matter, the stuff stars and planets are made of, and where it ended up.

What they found was a universe in flux. Before a pivotal moment called the epoch of reionization — when the universe finally became transparent to ultraviolet light — the gas was indeed mostly cold. It was the perfect, dense environment for star formation. But as star formation really picked up, and that intense ultraviolet light started zipping around, things changed. The simulations showed that the gas quickly shifted, becoming dominated by a warm, less dense phase. It’s like the universe went from a quiet, cool morning to a bustling, sun-drenched afternoon, with all that energy from new stars and radiation heating things up.

This wasn't just a minor temperature change. It fundamentally altered the rhythm of galaxy evolution. The team's clever simulations traced the journey of various types of gas, carefully avoiding the usual shortcuts in models that can often lead to fuzzy answers. They found some eye-opening things about how these infant galaxies put themselves together.

For starters, the stellar return fraction was surprisingly low. This is the amount of material that stars eject back into the surrounding gas when they die, essentially recycling fuel for the next generation of stars. In the early universe, it seems, stars were less efficient at this recycling. Lower quantities of old stellar material returned to the gas, meaning that new stars largely formed from fresh, pristine gas constantly falling in from the cosmic web. It's a bit like a construction site that keeps getting new materials delivered rather than reusing much from demolished buildings.

But even with less recycling, these galaxies were burning through their gas at an astonishing rate. Maio and Péroux discovered that the depletion times — the time it would take for a galaxy to convert all its gas into stars at its current rate — were incredibly short. Much shorter than we see in galaxies today. This means that early galaxies were true star-forming machines, gobbling up gas and spitting out stars with a furious intensity. It paints a picture of baby galaxies throwing one heck of a tantrum, furiously making stars with every available bit of gas.

So, why does any of this matter? Because it rewrites a part of our cosmic origin story. Our initial predictions for these early galaxies, based on observations of later, more mature galaxies, simply weren't capturing this dynamic, rapidly evolving picture. It turns out that you can't just take what you know about middle-aged galaxies and apply it to their energetic youth. The physical processes, from gas dynamics to stellar feedback, are just too different when the universe itself is so young and compact.

Of course, this cosmic detective story is far from over. Numerical simulations are powerful, but they’re always battling with the sheer complexity of the universe. Modeling everything from the intricate, multi-phase structure of gas to the powerful winds blown out by massive stars and black holes is a huge challenge. There are still big uncertainties, like the exact initial mass function of stars (how many big stars versus small stars are born) and the precise amount of "metals" needed to kickstart cooling. Our models still have plenty of room to grow.

But the good news is, we’re armed with ever more powerful tools. The James Webb Space Telescope is out there, giving us sharper and sharper images of these distant, ancient galaxies. And coming down the pipeline are next-generation radio telescopes, like the Square Kilometer Array (SKA), which will let us peer even deeper into the cold gas reservoirs of these early galaxies. These new eyes on the sky will give us the crucial real-world data needed to test these new theoretical predictions, helping us refine our models and paint an even clearer picture of the universe's chaotic, yet beautiful, beginnings.

The journey to understand how the universe built itself, one galaxy at a time, is still unfolding before us.

Staring up at the night sky, you might envision a star flaring up, burning thousands of times brighter than usual. That's a cosmic explosion —  a supernova! Except it isn't. The star lives on.

These violent, non-fatal eruptions can make a star mimic a true supernova — leading to what we affectionately call "supernova impostors."

These are massive stars, prone to titanic temper tantrums, blasting out huge amounts of their own material. Astronomers call this "eruptive mass loss," and it's a stellar drama we're still trying to fully grasp.

Trying to understand these supernova impostors is like trying to weigh a raging volcano's output without getting too close. We know it's important, but measuring how much material these stars eject, and what makes them do it, is surprisingly hard.

Current ways of measuring mass loss from, say, infrared or radio observations, typically only show us what's happening right now. But these stars spit stuff out in fits and starts, not a steady stream. And when we try to average it all out across stellar populations, we lose the juicy details of individual star behavior.

For decades, astronomers have concocted intricate computer models to predict how stars live and die. These stellar evolution tracks are our cosmic crystal balls. But for truly gargantuan stars, the models often sputter out, unable to complete their lives in the simulation. One big sticking point? This very same eruptive mass loss.

Models include a way to describe it, imagining light pressure pushing material off the star, exceeding its stable luminosity limit – what scientists call super-Eddington conditions.

But the key to making this work is a free-floating efficiency parameter – a dial that controls the strength of the outburst. And nobody knew where to set it. It was a crucial, unconstrained value, holding back our understanding of how these cosmic giants evolve.

The struggle to accurately model these phenomena means that despite growing observational evidence of violent eruptions, the underlying physical mechanisms remain poorly understood.

But astronomers are a clever bunch. A team led by Shelley J. Cheng at the Center for Astrophysics | Harvard & Smithsonian, along with Charlie Conroy and Jared A. Goldberg, decided to tackle this problem head-on in a new study posted to arXiv.

Their idea? Instead of trying to measure every little burp from a single giant, they'd take a census of red supergiants across our nearby galactic neighbors – what we call the Local Group stellar populations. These are massive stars in their later stages, swollen and ruddy, shining bright across the cosmos. We know where they live. We know what they look like.

Wide-field surveys, like the PanSTARRS1 Medium-Deep Survey, have revolutionized our ability to spot these peculiar transients and luminous outbursts, helping us map out these red giants in distant galaxies. This observational power is crucial for gathering the data needed to calibrate eruptive mass loss.

The team used sophisticated MESA stellar evolution models, tweaking that mysterious efficiency parameter to see what happened. Then, they created mock stellar populations – basically, fake galaxies brimming with these modeled stars, sampling different initial masses and ages, just like real star-forming regions.

They then compared the predicted brightness distributions of these mock stars to actual observations of red supergiants in the Small Magellanic Cloud, the Large Magellanic Cloud, and the Andromeda galaxy (M31). It was like trying to match a blurry photo of a crowd to a lineup of suspects, carefully adjusting until the picture clicked.

What they found was that the efficiency parameter wasn’t just some random number. It showed a clear, positive trend with metallicity  —  the amount of heavy elements baked into a star.

More heavy elements, more violent eruptions. It's a bit like adding more baking soda to a volcano experiment – things get livelier.

With this calibrated eruptive mass loss, stars that start out truly massive – over about 20 times the sun's heft – are prevented from ever even becoming red supergiants in the models. Instead, these colossal stars shed so much material in their dramatic outbursts that they skip that red supergiant phase entirely, evolving down a different path.

But the universe, as always, holds more cards. This relationship between mass loss and metallicity looks solid, but we need to test it in more galaxies, not just our immediate neighbors, to confirm the trend is truly widespread. Future simulations will also need to dig into the nitty-gritty: Does metallicity affect what triggers an eruption, or just how much stuff escapes?

The saga of these spitting stars is far from over. Each new burst of observation, each refined model, peels back another layer, showing us just how dynamic and surprising the life of a star can be.