The Helium Star Donor Channel for the Progenitors of Type Ia Supernovae and their Surviving Companion Stars

The nature of type la supernovae (SNe Ia) is still unclear. Employing Eggleton's stellar evolution code with the optically thick wind assumption, we systematically studied the He star donor channel of SNe La, in which a carbon-oxygen white dwarf accretes material from a He main-sequence star or a He subgiant to increase its mass to the Chandrasekhar mass. We mapped out the initial parameters for producing SNe la in the orbital period secondary mass plane for various WD masses from this channel. According to a detailed binary population synthesis approach, we find that this channel can produce SNe Ia with short delay times (similar to 100 Myr) implied by recent observations. We obtained many properties of the surviving companions of this channel after SN explosion, which can be verified by future observations. We also find that the surviving companions from the SN explosion scenario have a high spatial velocity (>400 km/s), which could be an alternative origin for hypervelocity stars (HVSs), especially for HVSs such as US 708.