2004ApJ...601.1058I

The evolution of binaries consisting of evolved main-sequence stars (1<M_d/M_☉<3.5) with white dwarf companions (0.7<M_wd/M_☉<1.2) is investigated through the thermal mass-transfer phase. Taking into account the stabilizing effect of a strong, optically thick wind from the accreting white dwarf surface, we have explored the formation of several evolutionary groups of systems for progenitors with initial orbital periods of 1 and 2 days. The numerical results show that CO white dwarfs can accrete sufficient mass to evolve to a Type Ia supernova, and ONeMg white dwarfs can be built up to undergo accretion-induced collapse for donors more massive than about 2 M_☉. For donors less massive than ∼2 M_☉, the system can evolve to form an He and CO or ONeMg white dwarf pair. In addition, sufficient helium can be accumulated (∼0.1 M_☉) in systems characterized by 1.6≲M_d/M_☉≲1.9 and 0.8≲M_wd/M_☉≲1 such that sub-Chandrasekhar-mass models for Type Ia supernovae, involving off-center helium ignition, are possible for progenitor systems evolving via the Case A mass-transfer phase. For systems characterized by mass ratios ≳3, the system likely merges as a result of the occurrence of a delayed dynamical mass-transfer instability. We develop a semianalytical model to delineate these phases that can be easily incorporated in population synthesis studies of these systems.