On the evolutionary time scale of the accreting component in massive close binaries

The remaining core hydrogen burning after mass exchange is computed for the mass gaining component in massive close binary systems. Results are obtained for various models of mass accretion, for a wide range of initial masses and mass ratios, and for different values of mass loss from the system. The position in time is determined for the end of core hydrogen burning of the primary and secondary, and the occurrence of the supernova of the primary and secondary. A generalized time-sequence of massive close binary evolution is also derived for a wide range of system parameters. It is found that the two supernova events occur rather close in time, as compared to the main sequence time scales of the components.