WD+RG systems as the progenitors of Type Ia supernovae

TL;DR

This study investigates the white dwarf + red giant progenitor channel for Type Ia supernovae, emphasizing the impact of accretion disk instability on binary evolution and the resulting implications for supernova progenitors and low-mass white dwarf formation.

Contribution

It provides detailed binary evolution calculations considering accretion disk instability, mapping initial parameters for SNe Ia in the WD+RG channel, and explores the formation of low-mass white dwarfs.

Findings

Long-period dwarf novae can produce SNe Ia.

Surviving companions are low-mass stars (<0.45Msun).

Accretion disk instability affects the progenitor parameter space.

Abstract

Type Ia supernovae (SNe Ia) play an important role in the study of cosmic evolution, especially in cosmology. There are several progenitor models for SNe Ia proposed in the past years. In this paper, by considering the effect of accretion disk instability on the evolution of white dwarf (WD) binaries, we performed detailed binary evolution calculations for the WD + red-giant (RG) channel of SNe Ia, in which a carbon-oxygen WD accretes material from a RG star to increase its mass to the Chandrasekhar mass limit. According to these calculations, we mapped out the initial and final parameters for SNe Ia in the orbital period--secondary mass plane for various WD masses for this channel. We discussed the influence of the variation of the duty cycle value on the regions for producing SNe Ia. Similar to previous studies, this work also indicates that the long-period dwarf novae offer a possible ways for producing SNe Ia. Meanwhile, we find that the surviving companion stars from this channel have a low mass after SN explosion, which may provide a means for the formation of the population of single low-mass WDs (<0.45Msun).