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.Comment: 7 pages, 2 figures, accepted by Res. Astron. Astrophys
