THE FORMATION OF A GASEOUS FLOW IN THE VICINITY OF THE INNER LAGRANGIAN POINT - 2-DIMENSIONAL VERSION

The two-dimensional version of the problem on the flow formation in th e inner Lagrangian point been investigated in the case of the close bi nary system XZ Cephei. For this purpose, the system of nonstationary e quations of hydrodynamics in Euler form has been used, the integration of which has been made with the <<coarse particles>> method by Belots erkovsky and Davydov; neither the role of Coriolis forces nor possible radiation pressure were taken into consideration, the companion's syn chronous rotation around its axis and around the common centre of mass of the system were assumed. As an initial atmosphere, the one taken f rom Kurucz Atlas of stellar atmospheres was used; its parameters prove d to be chose to those of the companion. The results of calculations i ndicate that the flow sizes and velocity in the first libration point depend essentially on the degree of filling of the Roche lobe by the c ompanion. At the concentration of 1,67 . 10(12)-6 . . 10(14) cm-3 in t he inner Lagrangian point, the velocity and flow radius change within the range of 12-25 km/s and 0,035-0,155 A (A is the distance between t he centres of components). The velocity turns out to be near that of t he local sound. The above results agree mainly with the suppositions o n the flow properties in the first libration point which were made by Lubov and Shu in their work on the motion of gaseous flows in close bi nary systems (1975). The determination of the flow sizes in the plane perpendicular lo the orbital one indicates that the flow in the vicini ty of the inner Lagrangian point has an axial symmetry. The symmetry a xis coincides with the line connecting the components' centres.