Mass flow due to heating in a binary system - Application to U Cephei

The possibility of mass flow due to the heating of the cooler component in a close binary system has been investigated. The heating may be caused by irradiation from the hotter companion or by other mechanisms such as the spacial coincidence of non-linear 'g-mode' oscillations in the cooler star. The 2.4-day period binary U Cep, in which gas streaming has been observed, has been chosen for model calculations. Preliminary results show that such a heating of the lower atmosphere of the cooler star could lead to mass flow at an average rate of 10 to the -9th - 10 to the -7th solar mass per year without the star necessarily filling its critical Roche surface.