Big explosion noted

Runaway anti-matter production makes for a spectacular stellar explosion

University of Notre Dame astronomer Peter Garnavich and a team of collaborators have discovered a distant star that exploded when its center became so hot that matter and anti-matter particle pairs were created. The star, dubbed Y-155, began its life around 200 times the mass of our Sun but probably became "pair-unstable" and triggered a runaway thermonuclear reaction that made it visible nearly halfway across the universe....

Garnavich and his collaborators calculated that, at its peak, Y-155 was generating energy at a rate 100 billion times greater than the sun's output. To do this, Y-155 must have synthesized between 6 and 8 solar masses of radioactive nickel. It is the decay of radioactive elements that drives the light curves of supernovae. A normal "Type Ia" thermonuclear supernova makes about one tenth as much radioactive nickel.

"In our images, Y-155 appeared a million times fainter than the unaided human eye can detect, but that is because of its enormous distance," Garnavich said. "If Y-155 had exploded in the Milky Way it would have knocked our socks off."

Over 40 years ago scientists proposed that massive stars could become unstable through the production of matter/anti-matter particle pairs, but only recently have large-scale searches of the sky, like the ESSENCE project, permitted the discovery of these bright, but rare, events.

Maybe we just live in a lucky corner of the universe.