Abstract

Contributed Talk - Splinter CloseBinaries   (MW-0250)

The population of compact sdB-WD binaries and their role as double detonation progenitors

Eric Stringer
University of Hamburg

Type Ia supernovae have been instrumental in cosmology for their use as standard candles to measure extragalactic distances. They have long been understood to arise from the thermonuclear detonation of a white dwarf (WD), itself caused by the WD reaching the Chandrasekhar limit. However growing evidence suggests that these supernovae can also occur at sub-Chandrasekhar masses through the double detonation channel. In this channel, the WD accretes helium-rich material from a companion star and a helium layer builds up on its surface. After accreting ∼ 0.1M⊙, this helium layer will detonate causing the WD to compress. This triggers a carbon fusion chain reaction, exploding the star prematurely. One class of helium-rich stars known as hot subdwarfs (sdBs) are often found in binaries with WDs. When these binaries are born with orbital periods ≲ 2 hours, they have the potential to engage in the helium mass transfer required for a double detonation. This makes them exciting progenitor systems to explore for double detonation supernovae. In this talk, I will discuss the population of compact WD-sdB binaries, highlight several intriguing systems undergoing stable mass transfer, and explore their potential contribution to observed Type Ia supernovae.