Nov. 22, 2006 — Stars are blowing themselves to smithereens more often than usual in galaxy NGC 1316. Astronomers have stumbled onto two supernovae letting loose there just months apart, in addition to two previous mega-blasts in the last 26 years.
That makes the rate of exploding stars in NGC 1316 many times higher than any other known galaxy.
The recent twin supernovae were detected by the NASA Swift satellite observatory on June 19 and Nov. 5 of this year. In the images, the supernovae are visible on either side of the bright galaxy center.
"It is actually very puzzling," said Neil Gehrels, a Swift investigator at NASA's Goddard Space Flight Center. "That's the most (supernovae) there have ever been in such a short time." A more typical rate is around one a century in a given galaxy.
So what makes NGC 1316 different? Not a lot, at least so far as researchers can tell. It's a large elliptical galaxy about 80 million light years away, believed to have recently collided and merged with a spiral galaxy, which may have something to do with the accelerated rate of supernovae — or not.
Galactic mergers are believed to stir up cosmic dust in a way that can create supermassive stars — the sort that eventually explode as supernovae.
But the supernovae in NGC 1316 have the spectral fingerprints of Type 1A supernovae, which begin as small, dying white dwarf stars rather than supermassive ones.
