On the progenitors of type Ia supernovae

The progenitors of type Ia supernovae (SNe Ia) are still under debate. There are two popular progenitor models for the formation of SNe Ia, i.e. the double-degenerate (DD) model and the single-degenerate (SD) model. However, none of these models can explain all of the observed properties of SNe Ia. In this paper, we introduce the white dwarf+helium (WD+He) subgiant channel in the context of the DD model and the semidetached WD+red-giant (RG) channel in the context of the SD model: (1) after considering the WD+He subgiant channel, the theoretical delay-time distribution of SNe Ia from the DD model can reproduce the observed results better; (2) by using an updated mass-transfer method for the semidetached WD+RG systems (varying with the local material states), the initial parameter space and SN Ia birthrate from the semidetached WD+RG channel is enlarged significantly.