Type Ia Supernova Explosions in Binary Systems: The Impact on the Secondary Star and its Consequences

Abstract

One method of discriminating between the many Type Ia progenitor scenarios is by searching for contaminating hydrogen and helium stripped from the companion star. We present several high-resolution 2-D numerical simulations of the impact of a Type Ia supernova explosion with hydrogen-rich main sequence, subgiant, and red giant companions. The binary parameters were chosen to represent several classes of single-degenerate Type Ia progenitor models that have been suggested in the literature. We use realistic stellar models and supernova debris profiles to represent each binary system. For each scenario, we explore the hydrodynamics of the supernova-secondary interaction, calculate the amount of stellar material stripped from the secondary and the kick delivered by the impact, and construct the velocity and solid angle distributions of the stripped material. After the impact, the main sequence star is puffed up, much like a pre-main sequence star. The subgiant companion behaves similarly. The secondary will not be contaminated by much supernova debris from the initial impact, but it may accrete low-velocity iron-group elements (or oxygen and silicon if the ejecta is radially mixed) at late times. A He pre-white dwarf will be left behind after a supernova explosion with a red giant companion.