Supernova without an off switch... Jul 22, 2005 6:17:42 GMT -6
Post by Chicago Astronomer Joe on Jul 22, 2005 6:17:42 GMT -6
The supernova that just won't fade away
Using ESA’s XMM-Newton space observatory, a team of astronomers has discovered that this supernova, called SN 1979C, shows no sign of fading. The scientists can document a unique history of the star, both before and after the explosion, by studying rings of light left over from the blast, similar to counting rings in a tree trunk.
“This 25-year-old candle in the night has allowed us to study aspects of a star explosion never before seen in such detail,” said Dr Stefan Immler, leader of the team, from NASA’s Goddard Space Flight Center, USA. “All the important information that usually fades away in a couple of months is still there.”
Among the many unique finds is the history of the star’s stellar wind dating back 16 000 years before the explosion. Such a history is not even known about our Sun. Also, the scientists could measure the density of the material around the star, another first. The lingering mystery, though, is how this star could fade away in visible light yet remain so radiant in X-rays.
In identifying the history of the star that created SN 1979C, the team found that this star, about 18 times more massive than our Sun, produced fierce stellar winds. That material was flung into space for millions of years, creating concentric rings around the star.
The X-rays - produced after the explosion when the supernova shock caught up with the stellar wind and heated it to a temperature of several million degrees - illuminated 16 000 years’ worth of stellar activity.
“We can use the X-ray light from SN 1979C as a ‘time machine’ to study the life of a dead star long before it exploded,” said Immler.
More here: www.physorg.com/news5342.html
Boy, I would hate to be within a few light years of that explosion!