exploding white dwarfs

Abi Polin (Berkeley) came through NYU this week. Today she delivered a great seminar on explosions of white dwarfs. She is looking at different ignition mechanisms, and trying to predict the resulting supernovae spectra and light curves. This modeling requires a huge range of physics, including gastrophysics, nuclear reaction networks, and photospheres (both for absorption and emission lines). The current models have serious limitations (like one-d, which she intends to fix during her PhD), but they strongly suggest that type Ia supernovae (the ones that are created by white-dwarf explosions) do seem to come from a narrow mass range in white-dwarf mass. If you go too high in mass, you over-produce nickel. If you go too low in mass, you under-produce nickel and get way under-luminous. In addition to the NYU CCPP crew, Surabh Jha (Rutgers) and Armin Rest (STScI) were in the audience, so this talk was followed by a lively lunch! Jha suggested that the narrow mass range implied by the talk could also help with understanding the standard-candle-ness of these explosions.