1996A&A...305..468H

I discuss the effects of illumination of a main sequence star by high energy particles or gamma-ray photons on its structure. It is shown that energy can be deposited at large depths (up to about 100g/cm2) in the outer layers of the stellar envelope. This is deep enough for the circulation time scale of matter at the surface of the star to be longer than or comparable to the cooling time of the heated layers; the spherically symmetric assumption may therefore hold. In the case of low mass X-ray binaries, the illumination flux at these high energies is not sufficient to affect the scenario proposed by Hameury et al. (1993), and the secular evolution of these systems is not very different from that of unilluminated systems, although episodes with large mass transfer rates are expected. On the other hand, the situation is quite different in systems in which the compact object is a millisecond pulsar. A very significant expansion of the secondary is expected, which makes its total evaporation easier.