NASA's Chandra sees brightest supernova everMay 08, 2007The brightest stellar explosion ever recorded may be a long-sought new type of supernova, according to observations by NASA's Chandra X-ray Observatory and ground-based optical telescopes. This discovery indicates that violent explosions of extremely massive stars were relatively common in the early universe, and that a similar explosion may be ready to go off in our own Galaxy. "This was a truly monstrous explosion, a hundred times more energetic than a typical supernova," said Nathan Smith of the University of California at Berkeley, who led a team of astronomers from California and the University of Texas. "That means the star that exploded might have been as massive as a star can get, about 150 times that of our Sun. We've never seen that before." Astronomers think many of the first generation of stars were this massive, and, therefore, this new supernova may provide a rare glimpse of how the first stars died. It is unprecedented, however, to find such a massive star and witness its death in the local Universe. The discovery of the supernova, known as SN 2006gy, provides evidence that the death of such massive stars is fundamentally different from theoretical predictions. "Of all exploding stars ever observed, this was the king," said Alex Filippenko, leader of the ground-based observations at the Lick Observatory in California and the Keck Observatory in Hawaii. "We were astonished to see how bright it got, and how long it lasted." The Chandra observation allowed the team to rule out the most likely alternative explanation for the supernova, namely that it was an explosion of a white dwarf star with a mass only slightly higher than the Sun into a dense, hydrogen-rich environment. In that event, SN 2006gy should have been 1,000 times brighter in X-rays than what Chandra detected. "This provides strong evidence that SN 2006gy was, in fact, the death of an extremely massive star," said Dave Pooley of U.C. Berkeley who led the Chandra observations. The star that produced SN 2006gy apparently expelled a large amount of mass prior to exploding. This eruption is similar to one seen from Eta Carinae, a massive star in our Galaxy, raising suspicion that Eta Carinae may be poised to explode as a supernova. Although SN 2006gy is intrinsically the brightest supernova ever, it is in the galaxy NGC 1260 some 240 million light years away. However, Eta Carinae is only about 7500 light years away in our own Milky Way galaxy. "We don't know for sure if Eta Carinae will explode soon, but we had better keep a close eye on it just in case," said Mario Livio of the Space Telescope Science Institute in Baltimore, who was not involved in the research. "Eta Carinae's explosion could be the best star-show in the history of modern civilization." Supernovas usually occur when massive stars exhaust their fuel and collapse under their own gravity. In this case of SN 2006gy, astronomers think that a very different effect may have triggered the explosion. Under some conditions, the core of a massive star produces so much gamma-ray light that some of the energy from the radiation is converted into particle and anti-particle pairs. The resulting drop in energy causes the star to collapse under its own huge gravity. After this violent collapse, runaway thermonuclear reactions ensue and the star explodes, spewing the remains into space. The SN 2006gy data suggest that spectacular supernovas from the first stars -- rather than complete collapse to a black hole -- may be more common than previously believed. "In terms of the effect on the early Universe, there's a huge difference between these two possibilities," said Smith. "One pollutes the galaxy with large quantities of newly made elements and the other locks them up forever in a black hole." Chandra X-ray Center |
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| Related Supernova Current Events and Supernova News Articles Super Supernova: White Dwarf Star System Exceeds Mass Limit An international team led by Yale University has, for the first time, measured the mass of a type of supernova thought to belong to a unique subclass and confirmed that it surpasses what was believed to be an upper mass limit. CU-Boulder physics professors help create hottest temperature in universe Two University of Colorado at Boulder physicists are part of a collaborative team working with the U.S. Department of Energy's Brookhaven National Laboratory in New York that have created the hottest temperature matter ever measured in the universe -- 7.2 trillion degrees Fahrenheit. NASA's Fermi Closes on Source of Cosmic Rays New images from NASA's Fermi Gamma-ray Space Telescope show where supernova remnants emit radiation a billion times more energetic than visible light. The images bring astronomers a step closer to understanding the source of some of the universe's most energetic particles -- cosmic rays. Suzaku finds 'fossil' fireballs from supernovae Studies of two supernova remnants using the Japan-U.S. Suzaku observatory have revealed never-before-seen embers of the high-temperature fireballs that immediately followed the explosions. Fermi large area telescope points the way to new millisecond pulsars The discovery of seventeen new millisecond pulsars was announced today at the American Astronomical Society Meeting by scientists from the Naval Research Laboratory (NRL) Space Science Division and a team of international researchers. Giant Intergalactic Gas Stream Longer than Thought A giant stream of gas flowing from neighbor galaxies around our own Milky Way is much longer and older than previously thought, astronomers have discovered. The new revelations provide a fresh insight on what started the gaseous intergalactic streamer. Runaway anti-matter production makes for a spectacular stellar explosion University of Notre Dame astronomer Peter Garnavich and a team of collaborators have discovered a distant star that exploded when its center became so hot that matter and anti-matter particle pairs were created. Supernova Explosions Stay In Shape At a very early age, children learn how to classify objects according to their shape. Now, new research suggests studying the shape of the aftermath of supernovas may allow astronomers to do the same. Cosmic rays hunted down A thin rain of charged particles continually bombards our atmosphere from outer space. The mysterious particles were first detected 100 years ago but until 10 years ago when a new type of telescope began to come online physicists weren't sure where the "cosmic rays" came from or how they were generated. The first observations of the explosion of a star around 200 times the size of our sun reveals a new type of supernova What happens when a really gargantuan star - one hundreds of times bigger than our sun - blows up? Although a theory developed years ago describes what the explosion of such an enormous star should look like, no one had actually observed one - until now. More Supernova Current Events and Supernova News Articles |
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