The influence of deflagration to detonation transition density on type Ia supernovae

A widely accepted setting for type Ia supernovae (SNeIa) is a thermonuclear runaway occurring in a C/O white dwarf (WD) that gained mass from a companion. The peak brightness is determined by the mass of radioactive ⁵⁶Ni synthesized that powers the light curve. Models that best agree with observations begin with a subsonic deflagration that transitions to a supersonic detonation that rapidly incinerates the star. The condition under which the deflagration-to-detonation transition (DDT) occurs is largely uncertain and remains essentially a free parameter. We parameterize the DDT in terms of the local density because the characteristics of the burning wave dependmost sensitively on density. We present a study of the role of transition density in the DDT paradigm [1]. We apply a theoretical framework for statistically studying systematic effects using two-dimensional simulations that begin with a central deflagration having randomized perturbations. The DDT occurs when any rising plumes reach a specified density. We find a quadratic dependence of Fe-group yield on the log of DDT density. Assuming the DDT density depends on metallicity, we find the ⁵⁶Ni yield decreases 0.067±0. 004M⊙ for a 1 Z⊙ increase in metallicity.