[LINK] "Astronomers ID violent supernova"

[rfmcdonald]

Pop.

Astronomers have identified a massive supernova as a new type of violent stellar explosion predicted by physicists to exist, but never before seen.

Researchers say that the supernova 2007bi, first observed 2½ years ago, was the result of the collapse of a star 200 times the size of the sun and the resulting nuclear explosion.

The supernova took place in a dwarf galaxy about 1.35 billion light-years away.

Avishay Gal-Yam of the Weizmann Institute of Science in Israel and his colleagues say that the supernova's extreme brightness and its evolution over time are best explained by a pair-instability supernova. Their research is published this week in Nature.

The type of supernova is predicted to occur in super-massive stars that don't form a dense iron core but an oxygen core.

Particles of light — photons — in the oxygen core interact with the nuclei of atoms to form electrons and their equivalent anti-matter particle, positrons.

The conversion of photons to pairs of electrons and positrons causes a violent contraction in the star, leading to a runaway nuclear explosion.

Stars as big as the one that led to this supernova are thought to have been common in the early universe, so pair-instability supernovas may have played an important role in determining how the young universe evolved.

Another supernova, 2006gy, the brightest ever recorded, is also speculated to have been a pair-instability supernova.

Here is the relevant Wikipedia page. Suffice to it say that it's very bright and we all should be quite glad that the nearest possible supernova candidate, IK Pegasi, is not only 150 light-years away from us but likely to produce a pleasantly conventional supernova.