Stellar wind during helium nova outburst

Abstract

The mass ejection process during helium shell flashes on a 1.3 solar masses white dwarf which accretes pure helium matter is examined. Full cycles of helium shell flashes are followed by two different kinds of approaches: one is a time-dependent hydrostatic calculation, and the other is the construction of the sequence consisting of static models and steady state models with wind mass loss. It is found that a stellar wind occurs if the shell flash is strong enough, i.e., the mass accretion rate is lower than 1.7 x 10 to the -6th solar masses/year. The mass accumulation ratio, i.e., the ratio of the processed matter which remains after a shell flash to the initial envelope mass, has been obtained. This ratio depends strongly on the mass accretion rate. If the binary size is small enough, further mass loss occurs due to the outer critical Roche lobe overflow. This mass loss seriously affects the existing scenarios on the neutron star formation induced by the accretion. 31 refs.