ATLANTA Astronomers have found a bright blue companion star to an exploded supernova, a stellar survivor to one of the most violent eruptions in the universe.
The stars existence confirms theories that supernovas can live with cosmic companions, yet still be friendly enough not to destroy their neighbors in the process. A massive object 100,000 times brighter than the Sun, the newfound star sits on ground zero of a known supernova and not only survived the explosion, but influenced the event and its stellar aftermath, researchers said.
"The whole evolution of this system is affected by the companion star," explained Justyn Maund, the studys lead author, of the University of Cambridge in the United Kingdom. "The star actually altered the nature of supernova progenitor."
Give me that!
Supernovas mark the end of the road for stars much more massive than our Sun.
Instead of sitting idly by in a supernova explosion, the companion star apparently tore at its dying neighbor, ripping away about 10 solar masses of gas over a period of 250 years before the main event.
"The star basically stripped matter away from the supernova before the explosion, leaving just he core to explode," Maund said.
Finding the companion star helped astronomers answer some puzzling question about its supernova partner, SN 1993J. That star exploded in March of 1993 and was seen by astronomers on Earth, but the supernova had some bizarre traits. Instead of fading away like other stellar explosions, it experienced a sharp increase in brightness. Researchers, then, also saw unusually high amounts of helium gas in the supernovas remains.
"Astronomers just couldnt understand why the explosion was acting like this," Maund told SPACE.com. But interference from a companion star could do it, he added.
Maund and his colleagues used the Advanced Camera for Surveys aboard the Hubble Space Telescope, as well as the 10-meter Keck Telescope atop Hawaiis Mauna Kea to observe 1993J a decade after it went supernova. The research was announced here Wednesday at a meeting of the American Astronomical Society.
Supernovas occur when stars about eight times as massive as the Sun spend their nuclear fuel and collapse under their own weight. The outer layers of the star are ejected into space in a brilliant flash that can be brighter than an entire galaxy. The companion to 1993J is the first visible proof of what astronomers call Type 1A supernova, in which an exploding star sits within a binary system.
More to learn
Maund said astronomers were incredibly lucky with 1993J because the star that caused that supernova had been caught in a previous sky survey. It is only one of two stars imaged before going supernova the other was SN 1987A in the nearby Large Magellanic Cloud.
Over the last 10 years, the explosion has faded to the point that researchers were able to detect the supernovas companion star. In another decade they may even see what type of remnant 1993J will leave behind.
"It will be enough time for us to see whether the remains of this supernova will ultimately end in a neutron star, or maybe a black hole," Maund said.
advertisement
