A MODEL ATMOSPHERE INVESTIGATION OF THE EFFECT OF IRRADIATION ON THE SECONDARY STAR IN A DWARF NOVA

We compute some exploratory model atmospheres and synthetic spectra fo r red dwarfs which incorporate the phenomena of irradiation. These mod els are suitable for studies of the secondary stars of the shorter per iod dwarf novae. Our models show that the incident flux produces marke d changes in the temperature stratification and emitted spectra of the irradiated star. We investigate the effects of angle of incidence and , in an approximate manner, those of horizontal energy transfer. The l atter factor has a particularly strong effect on our results. Our resu lts have important implications for the interpretation of radial-veloc ity curves of dwarf novae.