Wednesday, July 3, 2013
Type Ia supernovae are the head on collisions of white dwarfs in triple systems
Boaz Katz, Member, Institute for Advanced Study, Princeton University
Note Unusual Venue - HAMEETMAN AUDITORIUM
We show that a few percent of moderately hierarchical triple systems consisting of 2 white dwarfs and an additional slightly more distant star, lead to the head on collision of the two white dwarfs. The inner white dwarf binaries have separations of few - few hundreds of AU, typical of observed binaries, implying that the rate of such collisions may be sufficient to account for type Ia supernovae. 2D hydrodynamical simulations of such collisions, in which the ignition process is fully resolved, show that several robust observational features including the range of 56^Ni of ~0.1Msun to 1Msun are recovered in this scenario without free parameters.