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, known as the symbiotic channel. However, previous studies on the symbiotic channel gave a relatively low rate of SNe Ia. In this Letter, we adopted an integrated mass-transfer prescription that is applicable for the mass-transfer from a RG star onto the WD. In this prescription, the mass-transfer rate varies with the local material states. 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 2-5% of all SNe Ia in our Galaxy. We suggest that the symbiotic systems RS Oph and T CrB are strong candidates for the progenitors of SNe Ia.
D. Liu, B. Wang, H. Ge, et. al.
Thu, 12 Oct 17
Comments: 5 pages, 5 figures, submitted to MNRAS Letter