NASA reports catastrophic, explosive death of a Star

US space agency, NASA announced on Monday that its Chandra X-ray Observatory and ground-based optical telescopes have witnessed the brightest stellar explosion ever recorded, indicating 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.

Astronomers speculate many of the first generation of stars were also extremely large, and this new supernova may thus provide a rare glimpse of how the first stars died.

U.S. astronomers using a variety of Earth and space telescopes found a giant exploding star, SN2006gy, that they figure has shined about five times brighter than any of the hundreds of supernovae ever seen before, 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.

“This was a truly monstrous explosion, a hundred times more energetic than a typical supernova,” said Smith. "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."

Smith labeled the SN2006gy as a ‘special kind of supernova’ that has never been seen before. SN2006gy, the brightest supernova ever, occurred long ago but was detected last year after its light traveled many, many trillions of km before it could be observed from Earth.

Occurred 240 million light years away in a galaxy called NGC 1260, the supernova was discovered in September 2006, and stands as far and away the most powerful and brightest ever observed.

A light year is approximately 6 trillion miles, the distance light travels in a year.

"Of all exploding stars ever observed, this was the king," said Alex Filippenko, leader of the ground-based observations at the Lick Observatory at Mt. Hamilton, California, and the Keck Observatory in Mauna Kea, Hawaii. "We were astonished to see how bright it got, and how long it lasted."

Observations from the Chandra X-ray telescope helped show that SN 2006gy didn't become a black hole like other supernovae and skipped a stage of star death. These observations also allowed astronomers to determine that this supernova was actually caused by the collapse of an extremely massive star, and not the most likely alternative explanation for the explosion, the destruction of a low-mass star.

Unlike other exploding stars that reach a peak brightness in days to a few weeks, SN2006gy peaked for 70 days and today, nearly eight months later, it still is as bright as a typical supernova at its peak, NASA said.

Dave Pooley of the University of California at Berkeley said the troubled and enigmatic star, thought to weigh in about 120 solar masses, appears similar to Eta Carinae, a massive star which perhaps is 100 to 120 times the mass of the sun and located 7,500 light years away within the Milky Way.

Astronomers say Eta Carinae could be about to perform the same celestial fireworks. There has not been a supernova in our galaxy in more than 400 years, Pooley said. Astronomers said the star which exploded polluted the surrounding environment with metals and elements that are needed for life.

Supernovas usually occur when massive stars exhaust their fuel and collapse under their own gravity, but in SN2006gy’s case scientists believe it was obliterated in an explosion which blasted all its material into space.

The Chandra X-ray Observatory is part of NASA's group of "Great Observatories" along with the Hubble Space Telescope, the Spitizer Space Telescope and the now de-orbited Compton Gamma Ray Observatory. Chandra allows the worldwide scientists to obtain unprecedented X-ray images of exotic environments to help understand the structure and evolution of the universe.

NASA's Marshall Space Flight Center, Huntsville, Alabama, manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Massachusetts.

The results from Smith and his fellow scientists will appear in The Astrophysical Journal.