Mass Accumulation Efficiency in Helium Shell Flashes for Various White Dwarf Masses

Abstract

We have calculated the mass accumulation efficiency during helium shell flashes on white dwarfs (WDs) of mass 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, and 1.35 Msolar for the helium accretion rates logMHe (Msolar yr-1)=-7.4 to -5.8. This efficiency is a crucial factor for binary evolutions of Type Ia supernovae. For less massive WDs (<0.8 Msolar) no wind mass loss occurs, and all the accreted mass accumulates on the WD if the Roche lobe size is large enough. The efficiency takes the minimum values in between 1.1 and 1.2 Msolar WD for a given mass accretion rate, as well as increases in both less and more massive WDs. The mass accumulation efficiency is larger than 0.5 for logMHe>=-6.72 in all the WD masses.