The helium star donor channel for the progenitors of type Ia supernovae and their surviving companion stars

TL;DR

This study explores the helium star donor channel as a pathway for type Ia supernovae, detailing the conditions for progenitor systems and properties of surviving companions, with implications for hypervelocity stars.

Contribution

It introduces a systematic analysis of the He star donor channel for SNe Ia, including initial parameter mapping and properties of surviving companions, supported by binary population synthesis.

Findings

The channel can produce SNe Ia with short delay times (~100 Myr).

Surviving companions have high velocities (>400 km/s).

Potential link to hypervelocity stars like US 708.

Abstract

The nature of type Ia 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 Ia, 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 Ia 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 (~100Myr) 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 (>400km/s), which could be an alternative origin for hypervelocity stars (HVSs), especially for HVSs such as US 708.