Detonation Initiation in Type Ia Supernovae*

Type Ia supernovae play a crucial role as standardizable candles for cosmology, but their stellar progenitors remain mysterious. Underlying this mystery is a crucial physical process: the mechanism of detonation initiation in Type Ia supernovae. Early suggestions for detonation initiation, based upon a detonation initiation mechanism originally proposed by Zel'dovich, cannot apply in the highly-turbulent conditions prevalent in major Type Ia supernova channels, in which the burning is disrupted into the distributed burning regime. We demonstrate, for the first time, using both analytic estimates and three-dimensional numerical simulations, how a carbon detonation may arise in a realistic three-dimensional turbulent electron-degenerate flow. We term this new mechanism turbulently-driven detonation. The turbulently-driven detonation initiation mechanism leads to a wider range of conditions for the onset of carbon detonation than previously thought possible, with important ramifications for SNe Ia models.