Revealing progenitors of type Ia supernovae from their light curves and spectra

TL;DR

This study uses radiation hydrodynamical simulations to investigate hydrogen signatures in light curves and spectra of type Ia supernovae, aiming to identify progenitor systems and interpret early observations.

Contribution

It provides new insights into the collision signatures in SNe Ia light curves and spectra, highlighting the need for more detailed models to confirm progenitor scenarios.

Findings

Weak shock emission may be due to underestimated gas-radiation coupling.

Early light curves do not exclude close binary progenitors.

Spectral features depend on viewing angles and can inform progenitor identification.

Abstract

In the single degenerate (SD) scenario of type Ia supernovae (SNe Ia), the collision of the ejecta with its companion results in stripping hydrogen rich matter from the companion star. This hydrogen rich matter might leave its trace in the light curves and/or spectra. In this paper, we perform radiation hydrodynamical simulations of this collision for three binary systems. As a result, we find that the emission from the shock-heated region is not as strong as in the previous study. This weak emission, however, may be a result of our underestimate of the coupling between the gas and radiation in the shock interaction. Therefore, though our results suggest that the observed early light curves of SNe Ia can not rule out binary systems with a short separation as the progenitor system, more elaborate numerical studies will be needed to reach a fair conclusion. Alternatively, our results indicate that the feature observed in the early phase of a recent type Ia SN 2014J might result from interaction of the ejecta with a red giant companion star. We also discuss the dependence of spectral features of H alpha and Si II absorption lines on viewing angles and investigate whether they can constrain the event rate of the SD progenitor.