Double Detonation of Sub-Chandrasekhar White Dwarfs and Subluminous Type Ia Supernovae

Type Ia supernovae are thought to result from thermonuclear explosions of carbon-oxygen white dwarf stars. This model generally explains the observed properties with certain exceptions, like sub-luminous supernovae. Here we discuss the possibility of sub-Chandrasekhar WDs detonating due to the build up of a layer of helium on the C-O WD by accreting from a helium rich companion star to explain observed deviations such as subluminous type Ia. We also detail some of the energetics involved that will make such scenarios plausible.