Institute for Advanced Study Informal Astrophysics Seminar

The field of type Ia supernova (SN Ia) explosion physics is in a crisis. Decades of theoretical researches fail to demonstrate that successful explosions can be convincingly achieved from the popular single degenerate and double degenerate merger models. A growing number of observational evidences contradict these two popular scenarios to explain the SN Ia population. We argue that the direct white dwarf-white dwarf collisions in the field multiple stellar systems is the most promising mechanism to explain the SN Ia population. Not only do collisions explain several robust features across the entire SN Ia population, but also their predictions of the bi-modal Ni56 distributions in the ejecta are recently discovered observationally. I will discuss key observational tests on the collision models enabled by the All Sky Automatic Survey for SuperNovae (ASAS-SN)-- the most successful bright supernova survey at present.