According to a February 26 news release from the University of California, Berkeley, the discovery of a brilliant supernova in a nearby galaxy just six weeks ago is posing new questions about the nature of star explosions.
Dubbed SN 2014J, the gleaming supernova was discovered by a professor and his students in the United Kingdom on January 21, roughly one week following when the stellar blast first became visible as a pinprick of light in its galaxy, M82, 11.4 million light years away. The supernova is the brightest supernova seen from Earth since SN1987A was spotted 27 years ago, and may be the closest Type Ia supernova – the type used to measure cosmic distances – in over 77 years.
According to Georgia State University, supernovae are classified as Type I if their light curves exhibit sharp maxima and then die away gradually. The maxima may be about 10 billion solar luminosities. Type II supernovae have less sharp peaks at maxima and peak at about 1 billion solar luminosities. They die away more sharply than the Type I.
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, California, they discovered that the robotic telescope had actually taken a photo of it 37 hours after it appeared, unnoticed, on January 14.
By combining this observation with another opportune observation by a Japanese amateur astronomer, Filippenko’s team was able to determine that SN 2014J had unusual characteristics – it brightened more rapidly than expected for a Type Ia supernova and it exhibited the same unanticipated, rapid brightening as another supernova that KAIT discovered and imaged last year – dubbed SN 2013dy.
“Now, two of the three most recent and best-observed Type Ia supernovae are weird, giving us new clues to how stars explode,” said Filippenko, referring to a third, though apparently “normal,” Type Ia supernova, SN 2011fe, discovered three years ago. “This may be teaching us something general about Type Ia supernovae that theorists need to understand. Maybe what we think of as ‘normal’ behavior for these supernovae is actually unusual, and this weird behavior is the new normal.”
The first published paper describing the SN 2014J observations appeared online this week by The Astrophysical Journal Letters and will appear in the March 1 print issue.