A SUPERNOVA seen in 2005 may be a new type of cosmic explosion. What’s more, similar explosions may have scattered antimatter throughout our galaxy.
“SN 2005E” exploded in a galaxy 100 million light years away. A team led by Hagai Perets at the Weizmann Institute of Science in Rehovot, Israel, has concluded that it does not look like either of the well-known kinds of supernova.
The most frequently observed form is a core-collapse supernova, which happens after a massive young star has formed a large core of iron that collapses under its own gravity, releasing radiation that blows the outer layers of the star apart. They almost always occur in regions where massive new stars are forming. By contrast, SN 2005E was in the dark outskirts of its galaxy, where few new stars are forming. Core-collapse supernovae also spit out much more debris than SN 2005E did.
To date, the only other known supernova mechanism is a type 1a supernova, in which a small, dense white dwarf star steals hydrogen gas from a larger companion star. The gas builds up, gradually compressing the white dwarf until it reaches a critical point at which carbon starts to burn in an explosive thermonuclear reaction. SN 2005E doesn’t look …
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17 June 2009 by Stephen Battersby