Brightest supernova ever observed
A star 150 times bigger than our Sun has exploded, producing what astronomers believe to be a new type of supernova. Located some 240 million light years away, the death of the star was observed by NASA's Chandra X-ray Observatory and ground-based optical telescopes. The explosion lasted for about 70 days and at its peak was 100,000 million times brighter than the sun. '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 in Austin. '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.' Supernovas usually occur when massive stars exhaust their fuel and collapse under their own gravity to form a black hole. However, in the case of this supernova, now dubbed SN 2006gy, astronomers think that after the violent collapse, the star spewed its remains into space. 'In terms of the effect on the early universe, there's a huge difference between these two possibilities,' said Dr Smith. 'One pollutes the galaxy with large quantities of newly made elements and the other locks them up forever in a black hole.' Astronomers think many of the first generation of stars were as massive as the star which exploded, meaning that this new supernova may well provide a rare glimpse of how the first stars died. The star that produced SN 2006gy is thought to be similar to another massive star called Eta Carinae, which is located only 7,500 light years away in our own galaxy. Prior to exploding, the star expelled a large amount of mass, similar to that that seen from Eta Carinae. Given its distance from Earth, some suggest that if Eta Carinae does go supernova, it will be visible alongside the Sun. '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. 'Eta Carinae's explosion could be the best star-show in the history of modern civilization.'
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