STREAM FORMATION IN W-SERPENTIS-TYPE BINARIES

By the method proposed by Nazarenko (1993) and using observational data obtained by different authors, the physical conditions in the stream in the neighbourhood of the inner Lagrangian point L(1) were calculated for three interacting binary systems of W Ser-type: beta Lyr, V367 Cyg, RY Sct. It is shown, that as a result of the evolutional expansion of the mass losing component the deep layers of its atmosphere reach the neighbourhood of the first Lagrangian point L(1) and a stream of axial symmetric shape is formed. Its radius is comparable to the dimension of the mass losing component. The rate of the mass transfer increases up to 10(-5) M./yr The calculated parameters of the stream in the neighbourhood of the point L(1) explain the main observational properties of the investigated systems (existence of extended circumstellar matter with a developed structure, high mass transfer rate).