Imprints of the ejecta-companion interaction in Type Ia supernovae: main sequence, subgiant, and red giant companions

TL;DR

This study uses high-resolution hydrodynamic simulations to analyze supernova ejecta-companion interactions in Type Ia supernovae, revealing detailed characteristics of the ejecta hole, stripped material, and prompt X-ray emission, with implications for different companion star types.

Contribution

First simulation-based estimates of shock-heated envelope material and its role in prompt X-ray emission in Type Ia supernovae interactions.

Findings

Ejecta hole has a 40-50° opening angle with density reduced by a factor of 2-4.

Stripped companion material and contamination levels vary due to model assumptions and numerical diffusion.

Shock-heated envelope contributes significantly to prompt emission, with energy comparable to ejecta energy.

Abstract

We study supernova ejecta-companion interactions in a sample of realistic semidetached binary systems representative of Type Ia supernova progenitor binaries in a single-degenerate scenario. We model the interaction process with the help of a high-resolution hydrodynamic code assuming cylindrical symmetry. We find that the ejecta hole has a half-opening angle of 40--50$^\circ$ with the density by a factor of 2-4 lower, in good agreement with the previous studies. Quantitative differences from the past results in the amounts and kinematics of the stripped companion material and levels of contamination of the companion with the ejecta material can be explained by different model assumptions and effects due to numerical diffusion.We analyse and, for the first time, provide simulation-based estimates of the amounts and of the thermal characteristics of the shock-heated material responsible for producing a prompt, soft X-ray emission. Besides the shocked ejecta material, considered in the original model by Kasen, we also account for the stripped, shock-heated envelope material of stellar companions, which we predict partially contributes to the prompt emission. The amount of the energy deposited in the envelope is comparable to the energy stored in the ejecta. The total energy budget available for the prompt emission is by a factor of about 2-4 smaller than originally predicted by Kasen. Although the shocked envelope has a higher characteristic temperature than the shocked ejecta, the temperature estimates of the shocked material are in good agreement with the Kasen's model. The hottest shocked plasma is produced in the subgiant companion case.