Irradiation-driven mass transfer cycles in compact binaries

Andreas Buening, Hans Ritter

Published 2004-10-01Version 1

We elaborate on the analytical model of Ritter, Zhang, and Kolb (2000, A&A 360, 959) which describes the basic physics of irradiation-driven mass transfer cycles in semi-detached compact binary systems. In particular, we take into account a contribution to the thermal relaxation of the donor star which is unrelated to irradiation and which was neglected in previous studies. We present results of simulations of the evolution of compact binaries undergoing mass transfer cycles, in particular also of systems with a nuclear evolved donor star. These computations have been carried out with a stellar evolution code which computes mass transfer implicitly and models irradiation of the donor star in a point source approximation, thereby allowing for more realistic simulations than were hitherto possible. We find that low-mass X-ray binaries and cataclysmic variables with orbital periods less than about 6 hours can undergo mass transfer cycles only for low angular momentum loss rates. CVs containing a giant donor or one near the terminal age main sequence are more stable than previously thought, but can possibly also undergo mass transfer cycles.