Thermal Timescale Mass Transfer and the Evolution of White Dwarf Binaries
Abstract
The evolution of binaries consisting of evolved main-sequence stars (1<Md/Msolar<3.5) with white dwarf companions (0.7<Mwd/Msolar<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 Msolar. For donors less massive than ~2 Msolar, the system can evolve to form an He and CO or ONeMg white dwarf pair. In addition, sufficient helium can be accumulated (~0.1 Msolar) in systems characterized by 1.6<~Md/Msolar<~1.9 and 0.8<~Mwd/Msolar<~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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2004
- DOI:
- 10.1086/380561
- arXiv:
- arXiv:astro-ph/0310126
- Bibcode:
- 2004ApJ...601.1058I
- Keywords:
-
- Stars: Binaries: Close;
- Stars: Novae;
- Cataclysmic Variables;
- Stars: Evolution;
- Stars: Mass Loss;
- Stars: Supernovae: General;
- Astrophysics
- E-Print:
- 9 pages, 6 figures, Latex, emulateapj style, ApJ accepted