A SERIES OF THEORETICAL LINE-PROFILES FORMED IN THE IRRADIATED EXPANDING ATMOSPHERES OF CLOSE BINARY COMPONENTS

We studied the effects of irradiation on the line formation in the exp anding atmospheres of tl:le components of close binary systems. We con sidered a. two-level atom approximation in Non-LTE situation. The thic kness of the atmosphere is assumed to be twice that of the stellar rad ius. Expansion velocities are assumed to be as large as 50 mean therma l units. We have computed the lines using total optical depths 10(3), 10(4) and 10(5) at the line centre. The irradiation from the secondary is assumed to be one: five and tell times the self radiation. The lin e fluxes in the line of sight are calculated by using the total source function which is the sum of the source functions due to self radiati on and that due to irradiation. We notice that the expansion of the me dium produces P Cygni type profiles and the irradiation enhances the e mission in the lines although the equivalent widths reduce considerabl y.