Brightest supernova ever seen
JAMES RANDERSON
THE BRIGHTEST supernova ever seen has been observed by NASA's orbiting Chandra x-ray telescope. The enormous star explosion released about 100 times more energy than a typical supernova and at its peak was 100,000 million times brighter than the sun.
Highly unusual
It is highly unusual to observe the death of super-massive stars. "We understand rather little about the most massive stars in the universe," said Jane Drew, an astrophysicist at Imperial College London. "They are very rare so we get our hands on them not very often."
She said super-massive stars had a live fast, die young existence in astronomical terms. They typically burn for just 1 million years, while our sun has been in existence for more than 4.5 billion. "We know that they live short and very furious lives," she said. Usually, supernovas occur when stars exhaust their fuel and collapse. But astronomers think the SN 2006gy supernova was different. Its massive core may have produced so much gamma radiation that some of the energy was converted into particle and anti-particle pairs.
This produced a huge gravitational pull that tugged the star in on itself. The collapse triggered runaway thermonuclear reactions, which caused the explosion to spew star detritus into space.
Crucial for life
Such cosmic littering has been vital for the universe and crucial for life. Stars are factories which produce heavier elements such as iron, so without them life could not exist.
"Of all exploding stars ever observed, this was the king," said Alex Filippenko, leader of the observations at the Keck observatory in Mauna Kea, Hawaii, and the Lick observatory at Mount Hamilton, California.
"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 one team. "That means the star that exploded might have been as massive as a star can get, about 150 times that of our sun."
Closer to home in the Milky Way lies a star called Eta Carinae, some 7,500 light years away. It has been losing mass rapidly and looks as though it may develop into a supernova. It is hard to predict what it would look like to us, but some suggest it would be so bright that it would be visible alongside the sun in the day. —
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