Supernova: not what you thought - The majority of type Ia SNe may be the result of WD-WD direct collision, and core collapse SNe may be thermonuclear

TYPEAstrophysics Seminar
Speaker:Doron Kushnir
Organizer:Hagai Perets
Time:14:30 - 15:30
Location:Lidow 620

Type Ia: I will show that the majority of type Ia SNe may be the result of direct collisions of typical field CO-WDs in triple systems. The supporting evidences are: 1.  the rate of such collisions may be comparable to the SNe Ia rate, 2. in this case the nuclear detonation is due to a well understood shock ignition, devoid of commonly introduced free parameters such as the deflagration velocity or transition to detonation criteria, 3. the observed range of Ni56 among different explosions, including the tendency for faint SNe in elliptical galaxies and bright SNe in spirals, is explained as the result of the CO WDs mass range, 4. a unique feature of this model (doubly-peaked line profiles in nebular-phase spectra) has been found to be common among type Ia SNe. Core-collpase: I will demonstrate that ~10 seconds after core-collapse of a massive star, a thermonuclear explosion of the outer shells is possible for some initial density and composition profiles (assuming the neutrinos failed to explode the star). The explosion may lead to a successful supernova, as first suggested by Burbidge, Burbidge, Fowler and Hoyle (1957).