Three-dimensional simulations of the interaction between Type Ia supernova ejecta and their main sequence companions

Context. The identity of the progenitor systems of Type Ia supernovae (SNe Ia) is still uncertain. In the single-degenerate scenario, the interaction between the supernova blast wave and the outer layers of a main sequence companion star strips off hydrogen-rich material which is then mixed into the ejecta. Strong contamination of the supernova ejecta with stripped material could lead to a conflict with observations of SNe Ia. This constrains the single-degenerate progenitor model.
Aims: In this work, our previous simulations based on simplified progenitor donor stars have been updated by adopting more realistic progenitor-system models that result from fully detailed, state-of-the-art binary evolution calculations.
Methods: We use Eggleton's stellar evolution code including the optically thick accretion wind model and taking into account the possibility of the effects of accretion disk instabilities to obtain realistic models of companion stars for different progenitor systems. The impact of the supernova blast wave on these companion stars is followed in three-dimensional hydrodynamic simulations employing the smoothed particle hydrodynamics code GADGET3.
Results: For a suite of main sequence companions, we find that the mass of the material stripped from the companions range from 0.11 M_⊙ to 0.18 M_⊙. The kick velocity delivered by the impact is between 51 km s^-1 and 105 km s^-1. We find that the stripped mass and kick velocity depend on the ratio of the orbital separation to the radius of a companion, a_f/R. They can be fitted in good approximation by a power law for a given companion model. However, we do not find a single power law relation holding for different companion models. This implies that the structure of the companion star is also important for the amount of stripped material.
Conclusions: With more realistic companion star models than those employed in previous studies, our simulations show that the hydrogen masses stripped from companions are inconsistent with the best observational limits (≤0.01 M_⊙) derived from SN Ia nebular spectra. However, a rigorous forward modeling from the results of impact simulations with radiation transfer is required to reliably predict observable signatures of the stripped hydrogen and to conclusively assess the viability of the considered SN Ia progenitor scenario.