Theoretical Physics Colloquium

Origin of type Ia supernovae

by Prof. Marat Gilfanov (Max Planck Institute for Astrophysics)

Tuesday, January 29, 2019 from to (Asia/Kolkata)
at AG 69
Type Ia supernovae are thermonuclear explosions of massive white dwarfs and play a vital role in chemical evolution of the Universe. They are also a powerful tool employed in modern observational cosmology to measure cosmic distances. However, we still have no definitive model for their origin. The nuclear runaway that leads to the explosion can start in a white dwarf gradually accreting matter from a companion star until reaching the Chandrasekhar limit, or could be triggered by a merger of two white dwarfs in a compact binary system. The electromagnetic signatures of these two possible paths are very different. An accreting white dwarf burning hydrogen in nuclear fusion becomes a source of copious X-ray and UV photons prior to the supernova explosion. This offers the means to determine which path dominates. In my talk, I will describe observations and recent theoretical developments which mostly excluded the textbook scenario of an accreting white dwarf exploding upon reaching the Chandrasekhar limit from the list of plausible candidates for snIa progenitors.