A likely candidate of type Ia supernova progenitors: the X-ray pulsating companion of the hot subdwarf HD 49798

TL;DR

This paper suggests that the binary system HD 49798 and its white dwarf companion is a promising candidate for future type Ia supernova, based on stellar evolution modeling.

Contribution

It demonstrates through stellar evolution simulations that HD 49798 and its companion could produce a type Ia supernova, identifying it as a likely progenitor.

Findings

HD 49798 system can produce a SN Ia in future evolution.

The white dwarf companion is massive enough to lead to a supernova.

Other WD + He star systems may also produce SNe Ia.

Abstract

HD 49798 is a hydrogen depleted subdwarf O6 star and has an X-ray pulsating companion (RX J0648.0-4418). The X-ray pulsating companion is a massive white dwarf. Employing Eggleton's stellar evolution code with the optically thick wind assumption, we find that the hot subdwarf HD 49798 and its X-ray pulsating companion could produce a type Ia supernova (SN Ia) in future evolution. This implies that the binary system is a likely candidate of SN Ia progenitors. We also discussed the possibilities of some other WD + He star systems (e.g. V445 Pup and KPD 1930+2752) for producing SNe Ia.