Astronomers would love to predict supernovas: knowing when and how massive stars die would reveal a great deal about them. An observation of a particular supernova with the license-platish name SN 2010mc actually began 40 days before the final explosion, giving astronomers a lot of data about the final stages of its life. This type of star that produced SN 2010mc is pretty rare, but when it dies, it dies big. The telltale sign of impending doom for stars of this type turned out to be the shedding of a huge amount of mass; watching for that ejection could let astronomers predict some future supernovas.

Supernova SN 2010mc was spotted by the Palomar Transient Factory (PTF), which looks for supernovae and other one-time (transient) events in a wide swath of the sky. As the name suggests, light from SN 2010mc arrived at Earth in 2010. (The first supernova of the year was 2010a; the 27th was 2010aa. Thus, there were a lot before 2010mc, but I’m too lazy to work out what number that was.) Going back in the PTF archives, the researchers discovered a precurser outburst, from the same region of the sky, which occurred 40 days earlier. [Read more….]