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How the brown dwarf blows: Wind speed of a 'failed star' measured for 1st time

A brown dwarf, left, and Jupiter, right. The artist's conception of the brown dwarf illustrates the magnetic field and top of the atmosphere, which were observed at different wavelengths to determine wind speeds in a new study.
A brown dwarf, left, and Jupiter, right. The artist's conception of the brown dwarf illustrates the magnetic field and top of the atmosphere, which were observed at different wavelengths to determine wind speeds in a new study.
(Image: © Bill Saxton, NRAO/AUI/NSF)

Brown dwarf winds blow hard.

For the first time ever, astronomers have measured wind speed on a brown dwarf, or "failed star," an object heftier than a planet but not massive enough to host the fusion reactions that power stars. 

That speed, a new study reports, is around 1,450 mph (2,330 km/h) — more than four times faster than any gust we experience here on Earth. (The terrestrial record is 318 mph, or 512 km/h, set in 1999 by a tornado in Oklahoma.)

Related: Photos: most powerful storms of the solar system

The research team studied a brown dwarf called 2MASS J10475385+2124234, which is about 40 times more massive than Jupiter and lies 34 light-years from Earth. The scientists employed a novel strategy that was inspired by previous observations of Jupiter.

"We noted that the rotation period of Jupiter as determined by radio observations is different from the rotation period determined by observations at visible and infrared wavelengths," study lead author Katelyn Allers, an associate professor of physics and astronomy at Bucknell University in Lewisburg, Pennsylvania, said in a statement.

That's because the radio emissions are coming from electrons interacting with Jupiter's magnetic field, which is rooted deep in the planet's interior, she explained. The visible and infrared (IR) data, on the other hand, reveal what's happening in the gas giant's cloud tops. 

The difference between the two rotation rates therefore provides a measurement of wind speed in Jupiter's upper atmosphere. And it should be possible to gather similar data for brown dwarfs, which are like scaled-up gas giants, the team reasoned.

"When we realized this, we were surprised that no one else had already done it," Allers said.

So Allers and her colleagues did it. 

They gathered radio data on 2MASS J10475385+2124234 in 2018 using the Very Large Array telescope network in New Mexico. And they got the IR observations in 2017 and 2018 with NASA's Spitzer Space Telescope, which tracked the movement of a long-lived feature through the brown dwarf's upper atmosphere. (The researchers also studied a second brown dwarf, called WISE J112254.73+ 255021.5, but were unable to get the requisite IR information for that one.)

The data revealed that prevailing winds on 2MASS J10475385+2124234 flow east to west at roughly 1,450 mph, plus or minus 690 mph (1,110 km/h). That's considerably faster than the average winds in Jupiter's upper atmosphere, which zoom along at about 250 mph (400 km/h), the researchers said. 

Such a disparity is to be expected. After all, the brown dwarf is significantly warmer, and thus more energetic, than Jupiter. 2MASS J10475385+2124234 has an estimated temperature of 1,124 degrees Fahrenheit (607 degrees Celsius), whereas Jupiter's cloud tops are a frosty minus 230 F (minus 145 C).

The new results should help astronomers learn more about the complex dynamics of brown dwarf atmospheres, which are poorly understood. After all, researchers now have an actual wind-speed number, rather than a mere estimate, to plug into their models. 

"If you know how fast the wind speed is, you actually can get a pretty good handle on whether the atmosphere is dominated by banding or by circular storms," study co-author Johanna Vos, a postgraduate researcher at the American Museum of Natural History in New York, told Space.com.

Related: The Spitzer Space Telescope's greatest exoplanet discoveries

And applications of the new study, which was published online today (April 9) in the journal Science, go beyond brown dwarf research, both Allers and Vos said.

"The next step is to do this for an exoplanet orbiting a star," Vos said. "It's kind of opened up new possibilities, and I find that really exciting."

But not every exoplanet is open to this line of inquiry, she added; astronomers will have to content themselves with relatively cool gas giants that can be directly imaged, at least for the foreseeable future. (The technique won't work with "hot Jupiters," gas giants that orbit very close to their stars, Vos said. These planets are tidally locked, always showing their host stars the same face, making it difficult if not impossible to track large-scale atmospheric movement.)

And such work cannot be done with Spitzer anymore, because NASA recently retired the workhorse space telescope. It will be tough for NASA's Hubble Space Telescope to pick up the slack, Vos said; Hubble orbits Earth and therefore doesn't make the required lengthy, uninterrupted observations of distant targets. (Spitzer circled the sun in an Earth-trailing orbit.)

"I think JWST will be our next opportunity to do this," Vos said, referring to NASA's $9.7 billion James Webb Space Telescope, which is scheduled to launch next year. 

Many other researchers will be champing at the bit to use the powerful, flexible JWST once it comes online, so it may be tough to secure the requisite 20 or so consecutive hours on the scope, Vos said.

"We're still going to ask for it," she said. "We'll have to see."

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook

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  • rod
    This was an interesting report on winds at 2MASS J10475385+2124234. I dug a bit into this brown dwarf and found, "Allers et al., 2020 : 2MASS J10475385+2124234 is a T6.5 BD of 0.5 to 10 billion years with an estimated temperature of 880+/-76 K, a rotation period of 1.77 ± 0.04 hours and a magnetic field strength of 5.6 kG. The difference between radio period and infrared period implies a wind of +650 ± 310 m/s proceeding eastward. ", ref -http://exoplanet.eu/catalog/2mass_j10475385+2124234/
    It could be 0.5 to 10 billion years old based upon the modeling :) Using 42 Mjup mass and radius, 2 Rjup, a rotation period of 1.77 hours is about 70.496 km/s at its equator and mean density about 2.48 g cm^3. Much larger than Jupiter and spinning much faster too. Only about 34 light-years distance. Seems like a fun place to visit, should get plenty of windy days :)
    Reply
  • dfjchem721
    Those are some pretty fast wind speeds. You could really get some power from wind farms at 2MASS J10475385+2124234.

    Thinking about the atmosphere of this brown dwarf and Jupiter, I was reminded of studies attempting to find out if any exoplanets have oxygen in their atmospheres, a possible sign of life since it is commonly assumed that O2 is not a stable compound and would need a constant source for replenishment, and life is that very likely source.

    It worked for us. And thing out there with an O2 signature, rod?!
    Reply
  • rod
    dfjchem721, *an O2 signature*? Dave, I am not aware of any reports like this. I find it interesting in astronomy how the subject of *habitable* planet has changed over the years. Here is an example from 1911.

    “Venus is nearly as large as the earth and, as it is much nearer the sun, its temperature must be higher than that of the earth. The average temperature is estimated to be about 140 degrees F. Various phenomena appear to indicate that the planet is surrounded by a comparatively dense and cloudy atmosphere which, indeed, is apparently seen as a luminous border, in the transits of Venus over the sun’s disk, which occur once or twice in a century. This dense atmosphere strongly reflects the sun’s rays and thus prevents the surface of the planet from attaining a temperature too elevated for highly organized life. The planet would be regarded as habitable.” —Scientific American, March 1911", https://www.scientificamerican.com/article/newsflash-we-could-live-on-venus/
    Reply
  • rod
    FYI, I did find this in my trusty, home database. ""ABSTRACT The combination of high-contrast imaging and high-dispersion spectroscopy, which has successfully been use to detect the atmosphere of a giant planet, is one of the most promising potential probes of the atmosphere of Earth-size worlds. The forthcoming generation of extremely large telescopes (ELTs) may obtain sufficient contrast with this technique to detect O2 in the atmosphere of those worlds that orbit low-mass M dwarfs. This is strong motivation to carry out a census of planets around cool stars for which habitable zones can be resolved by ELTs, i.e. for M dwarfs within ∼5 parsecs. Our HARPS survey has been a major contributor to that sample of nearby planets...", https://www.eso.org/public/archives/releases/sciencepapers/eso1736/eso1736a.pdf
    Reply
  • dfjchem721
    From rod, on old Venus notions: "This dense atmosphere strongly reflects the sun’s rays and thus prevents the surface of the planet from attaining a temperature too elevated for highly organized life. The planet would be regarded as habitable.” —Scientific American, March 1911"

    They clearly did not have all the details of Venus! But it could be habitable, if you read enough of the posts by all the dreaming space explorers. They just have to replace its atmosphere, bring in (or dig up) a lot of water for golf courses and suburban sprawl. Otherwise, live a subterranean life. Nobody says you have to live "on" the planet to live on the planet! Imaginations run wild.....

    Let us hope the ELTs will find the oxygen. That would be a unique observation, apparently.

    Wait, looks like I may have found some O2 after all*:

    "The first observed extrasolar planetary atmosphere was made in 2001. Sodium in the atmosphere of the planet HD 209458 b was detected during a set of four transits of the planet across its star. Later observations with the Hubble Space Telescope showed an enormous ellipsoidal envelope of hydrogen, carbon and oxygen around the planet. This envelope reaches temperatures of 10,000 K. The planet is estimated to be losing (1-5)×108 kg of hydrogen per second. This type of atmosphere loss may be common to all planets orbiting Sun-like stars closer than around 0.1 AU. In addition to hydrogen, carbon, and oxygen, HD 209458 b is thought to have water vapor in its atmosphere."
    Sounds like a newly formed planet and/or its atmosphere. It won't be losing that quantity for a very long time, one imagines. You must have data on this one (which would be nice confirmation, or not, of this Wiki data at any rate).

    But they also note later that :

    "The presence of molecular oxygen (O2) may be detectable by ground-based telescopes, and it can be produced by geophysical processes, as well as a byproduct of photosynthesis by life forms, so although encouraging, O2 is not a reliable biosignature. >> In fact, planets with high concentration of O2 in their atmosphere may be uninhabitable.<< "
    end quotes

    That last observation (my >> <<) would tend to rule out earth at 20% oxygen (surely that qualifies as a "high concentration of O2"). And then they go on about abiogensis (one of my specialties, as you know!). Whoever wrote this might want to stick to the space stuff and forget about life and its formation, activity and longevity. They have a few gaps on that one......

    While O2 can clearly be produced by geophysical processes, it is not at all clear that those processes would last for billions of years, like the source of O2 on earth, which is not a geophysical process. Earth is believed to have fossilized photosynthetic algae dating back over 3 bya. No doubt a young planet like HD 209458 b most likely formed O2 by a nonbiological process since it is at high temperature and not exactly what even the wildest imagination would suggest is a habitable planet.

    Apparently the opinions of a habitable planet is ever-changing, even as we exchange these messages!

    To repeat: "Let us hope the ELTs will find the oxygen."


    * https://en.wikipedia.org/wiki/Extraterrestrial_atmosphere
    Reply
  • rod
    FYI. Venus has plenty of O2, in the form of CO2, so does Mars atmosphere. Given the law of abiogenesis (because the law of biogenesis is rejected in evolutionary biology), there should be plenty of vegetation growing on Mars and Venus too. In 1907 and 1943, this was the scientific consensus, especially about Mars. Martians Get Their Water from the Poles, also from 1943, Beings That Are Smarter Than Humans Inhabit the Galaxy Originally published in July 1943
    You are correct in stating, "Apparently the opinions of a habitable planet is ever-changing, even as we exchange these messages!"

    My observation, the definitions of a habitable planet need to be ever changing in view of the law of abiogenesis at work, everywhere in the universe according to consensus thinking :)--Rod
    Reply
  • dfjchem721
    Rod posted :
    "Venus has plenty of O2, in the form of CO2, so does Mars atmosphere. Given the law of abiogenesis (because the law of biogenesis is rejected in evolutionary biology), there should be plenty of vegetation growing on Mars and Venus too. "

    Sadly the environmental conditions (temperature mostly) place those planets outside the "Goldilocks Zone". You are playing with me now!

    Actually CO2 is not even close to O2. They have very different properties. In terms of aerobic life (animals, some bacteria, etc), C02 is a by-product of metabolism (non-photosynthetic) and O2 drives energy production via electron transport in mitochondria (forming CO2 as waste). In plants, it is CO2 that gets the electron from sunlight to build glucose, and O2 is its "waste" product. One life form's garbage is another life form's gold!

    For planetary atmospheres, O2 will typically not last long because it is pretty reactive, unless it is being constantly generated. This is classically shown on earth by "banded iron formations"*, sediments seen as far back as 3.7 bya. They likely result from repeated bouts of O2 generation by photosynthesis, whereby the O2 reacted with free iron ions in the oceans to form ferric oxides. These precipitated out to form the bands. One can see this happen a number of times in the first billions of years of life on earth.*

    Eventually, photosynthetic organisms finally gained a "permanent" foothold on the surface, and continued to produce oxygen at a steady rate up until today, or clearly we would not be here. That is why only O2 in exoplanets would likely indicate life, as long as the planet's remaining "air" does not contain nasty compounds that would prevent life like lots of CO2, sulfuric acid, etc. We all know CO2's greenhouse problem re Venus and are trying (not very well) to avoid that. Staying in the Goldilocks Zone is critical to life's survival. The absence of O2 does not eliminate the possibility of life, but may limit how advanced it can become.

    We would be looking for an inert atmosphere (non-reducing) with plenty of oxygen, assuming there are places like earth close enough to get the data.

    Nothing in your data base on HD 209458 b? Thought it would show that the oxygen as suggested by the link I posted.

    https://en.wikipedia.org/wiki/Banded_iron_formation
    Reply
  • rod
    dfjchem721 (Dave). In 1907-1943, according to consensus science, it was common to see that Venus could be habitable as well as Mars with vegetation. CO2 was in the atmosphere and on earth, CO2 is something that plants love :) That seemed like a logical position concerning the law of abiogenesis for the origin of life on Earth. Who decided to look at exoplanets with O2 only vs. CO2 abundance as evidence of life or supporting life? If the law of abiogenesis is indeed at work in the universe, I would think plants would evolve on exoplanets, rich with CO2 atmospheres as well. Mars has always been considered to be habitable, just like meteorite reports of ALH84001 during the Clinton Administration and 1907 reports of vegetation on Mars or 1943. This goes to the heart of the methodology used to determine a habitable exoplanet with life on it and defining. O2 is today's gold, what about plants using CO2?
    Reply
  • dfjchem721
    Firstly, there is no "law of abiogenesis", but there probably should be. Just like there should be a "law of biological evolution".

    There is general consensus among biochemists that original life forms arose in a reducing atmosphere that did not contain O2. Energy was derived from chemicals within the seas (likely from thermal vents), since photosynthesis would require a highly evolved life form. Trapping photons and converting them into chemical energy is not considered an early-stage evolutionary development, but rather a much later-stage. The complexity of such a process is rather profound.

    It is believed that RNA, not DNA, was the first biopolymer to generate life, and it is unstable in a high O2 environment (compared to DNA). That is why I mentioned that lack of O2 does not rule out life, but probably limits its complexity.

    Since photosynthesis is driven by a complex protein assembly known as the "photosynthetic reaction center", its evolution would have had to wait for the evolution of proteins into the biochemical mechanisms of life as we see it today. Such a process probably took 100s of millions of years.

    I am going to take a wild guess and suggest that "consensus science" from 1907-1943 has undergone some serious changes in places. Biochemistry would be near the top of the list! The structure of DNA was determined in 1953, and from it the first biopolymers of life (polynucleotides) started to be revealed, and the abiogensis of life could then be postulated on a more sound basis. The kick-start to the first living organism remains a complete mystery.
    Reply
  • rod
    Okay Dave :) The *law of abiogenesis* and *law of biological evolution* are not the same as Kepler's planetary laws, Newton's laws of motion, or gravity. Astronomy has documented these laws operate in other areas of the solar system and universe too, e.g. binary stars, exoplanets, the orbits of the Galilean moons. The *law of abiogenesis* and *law of biological evolution* is not documented in other places. *The kick-start to the first living organism remains a complete mystery*. Good objective science answer :)--Rod
    Reply