Influence on binary evolution of X‐ray and γ‐ray irradiation of companions

Hard X‐rays and γ‐rays can be produced by accreting black holes and neutron stars. Black hole candidates and hard X‐ray transients emit most of their accretion luminosity in the hard X‐ray and soft γ‐ray spectral band. However, as shown by recent SIGMA observations of X‐ray bursters near the galactic center region, also accreting neutron stars produce transient emission of hard X‐rays. High‐energy irradiation of companion stars can drive mass outflows which can be substantially larger than intrinsic winds or outflows driven by binary angular momentum losses. We summarize here results of a computation of irradiation‐driven mass loss rates for accreting black hole and neutron star binaries.