The progenitors of type Ia supernovae in the semidetached binaries with red giant donors

TL;DR

This study revises the mass-transfer model in WD+RG systems, significantly enlarging the parameter space and increasing the predicted Galactic SNe Ia rate from the symbiotic channel, suggesting certain known systems as progenitors.

Contribution

It introduces a new integrated mass-transfer prescription that broadens the parameter space and enhances the SNe Ia rate from the symbiotic channel.

Findings

Parameter space for WD+RG systems producing SNe Ia is significantly enlarged.

The symbiotic channel could contribute up to 5% of all Galactic SNe Ia.

Model increases the SNe Ia rate from this channel by a factor of 5.

Abstract

Context. The companions of the exploding carbon-oxygen white dwarfs (CO WDs) for producing type Ia supernovae (SNe Ia) are still not conclusively confirmed. A red-giant (RG) star has been suggested to be the mass donor of the exploding WD, named as the symbiotic channel. However, previous studies on the this channel gave a relatively low rate of SNe Ia. Aims. We aim to systematically investigate the parameter space, Galactic rates and delay time distributions of SNe Ia from the symbiotic channel by employing a revised mass-transfer prescription. Methods. We adopted an integrated mass-transfer prescription to calculate the mass-transfer process from a RG star onto the WD. In this prescription, the mass-transfer rate varies with the local material states. Results. We evolved a large number of WD+RG systems, and found that the parameter space of WD+RG systems for producing SNe Ia is significantly enlarged. This channel could produce SNe Ia with intermediate and old ages, contributing to at most 5% of all SNe Ia in the Galaxy. Our model increases the SN Ia rate from this channel by a factor of 5. We suggest that the symbiotic systems RS Oph and T CrB are strong candidates for the progenitors of SNe Ia.