SIMBAD references

The discovery of supersoft X-ray sources, described as massive white dwarfs burning accreted matter from their (more massive) companions, opens a new channel to type Ia supernovae (SNe Ia). According to conventional binary evolutionary theory, if the mass ratio of the donor to the white dwarf exceeds a critical value, the mass transfer becomes unstable, and a common envelope will be formed. However, recent calculations by Hachisu, Kato & Nomoto (1996ApJ...470L..97H) suggest a strong wind to stabilize the mass transfer when the mass transfer rate is higher than a certain value. Adopting the strong wind assumption, we have performed evolutionary calculations of white dwarf binaries, in which mass transfer occurs through Roche-lobe overflow, to search for the progenitors of SNe Ia. We find that there are two types of systems that can produce SNe Ia. One is close binaries with ∼2 to ∼3.5M_☉ main-sequence or subgiant companions, and the initial orbital period of several tenth of a day to several days. The other is wide binaries with low-mass (∼1M_☉) red giant companions and long initial orbital period (tens to hundreds of days). The derived birth rate of SNe Ia in the Galaxy is roughly consistent with the observed one.