Brightest Supernova May Reignite
New supernova mechanism would set off repeat explosions
http://www.sciam.com/article.cfm?id=brightest-supernova-may-reigniteA new type of ultrapowerful supernova discovered last year may blow its top again, according to a new study.
Researchers report that supernova 2006gy fits a model of star explosion that should have produced two flare-ups already and may culminate in a third before the star fizzles out. A second study proposes that the explosion might have come about from the marriage of multiple stars.
SN 2006gy first caught astronomers' eyes in September. Burning 100 times brighter than a typical supernova, it maintained full strength for an amazing three months, by which point most of its counterparts would have begun fading. Even eight months later it was as brilliant as a so-called type II supernova, the most common variety. The energy unleashed implied that the exploding star was a behemoth of at least 100 solar masses (suns).
To explain SN 2006gy's massive outburst, researchers invoked a competing mechanism called pair-instability, which theoretically kicks in for stars larger than 90 suns. In this scenario, dating to 1967, high-energy gamma rays inside the star convert into pairs of electrons and positrons, draining stellar energy that would normally help maintain its internal pressure, eventually leading to a premature collapse that liberates vast amounts of energy and light. . . . .
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