Closest, brightest supernova poses new questions about exploding stars

A bright supernova found only six weeks back in a nearby galaxy is provoking new questions about the exploding stars, which researchers use as their main yardstick for measuring the universe.

Called SN 2014J, the glowing supernova was discovered by a professor and his students in the United Kingdom on Jan. 21, about a week after the stellar explosion first became visible as a pinprick of light in its galaxy, M82, 11.4 million light-years away.

When University of California, Berkeley, astronomer Alex Filippenko's research team looked for the supernova in data collected by the Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory near San Jose, Calif., they discovered that the robotic telescope had actually taken a photo of it 37 hours after it appeared, unnoticed, on Jan. 14.

Combining this observation with another chance observation by a Japanese amateur astronomer, Filippenko's team was able to calculate that SN 2014J had unusual characteristics-it brightened faster than expected for a Type Ia supernova and, even more intriguing, it exhibited the same unexpected, rapid brightening as another supernova that KAIT discovered and imaged last year-SN 2013dy.

Filippenko, referring to a third, though apparently 'normal,' Type Ia supernova, SN 2011fe, discovered three years ago, said that two of the three most recent and best-observed Type Ia supernovae are weird, giving us new clues to how stars explode, asserting that they may be teaching us something general about Type Ia supernovae that theorists need to understand.

The study has been published online in The Astrophysical Journal Letters.