By Xinhua
Washington : NASA has announced that its Chandra X-ray Observatory and ground-based optical telescopes see the brightest stellar explosion ever recorded, which may be a long-sought new type of supernova.
Supernovas usually occur when massive stars exhaust their fuel and collapse under their own gravity.
"Of all exploding stars ever observed, this was the king," said Alex Filippenko, leader of the ground-based observations. "We were astonished to see how bright it got, and how long it lasted."
"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."
Astronomers think many of the first generation of stars were this massive, and this new supernova may thus provide a rare glimpse of how the first stars died. It is unprecedented, however, to find such a massive star and witness its death.
The discovery of the supernova, known as SN 2006gy, provides evidence that the death of such massive stars is fundamentally different from theoretical predictions.
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.
The star that produced SN 2006gy apparently expelled a large amount of mass prior to exploding. This large mass loss is similar to that 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 the brightest supernova ever, it is in the galaxy NGC 1260, some 240 million light years away. However, Eta Carinae is only about 7,500 light years away in our own Milky Way galaxy.