Title: From Subdwarfs to Type Ia Supernovae

Speaker: Dr. Kunal Deshmukh, Texas Tech University

Abstract: Hot Subdwarfs are post-main sequence helium core burning stars found on or near the Extreme Horizontal Branch on the HR diagram. Most subdwarfs reside in binary systems. Compact hot subdwarf binaries result from one (or more) common envelope ejection phase(s) that can lead to orbital periods ≲2 hr. Such short periods are subject to considerable orbital decay through emission of gravitational waves, and can potentially lead to mass transfer. In the special case of a subdwarf-white dwarf binaries, the subdwarf can accrete helium rich material onto the white dwarf and cause a sub-Chandrasekhar detonation leading to SNe Ia. Although predicted in theory for a while now, it is only in recent years that studying this channel for SNe Ia observationally has been boosted owing to surveys such as ZTF and LAMOST. Detailed stellar evolution tools such as MESA have also enabled modelling of such systems. In this talk, I will briefly cover the formation and properties of subdwarfs in general, and discuss in detail the latest results on observations and modelling of compact subdwarf binaries as SN Ia progenitors.