Type Ia Supernovae from Sub-Chandrasekhar Mass White Dwarfs

We argue that detonations of sub-Chandrasekhar mass white dwarfs can lead to bright explosions with light curves and spectra similar to those of observed Type Ia supernovae. Given that binary systems containing accreting sub-Chandrasekhar mass white dwarfs should be common, this suggests that a non-negligible fraction of the observed Type Ia supernova rate may arise from sub-Chandrasekhar mass explosions, if they can be ignited. We discuss aspects of how such explosions might be realized in nature and both merits and challenges associated with invoking sub-Chandrasekhar mass explosion models to account for observed Type Ia supernovae.