Doublet 2800 Mg II in close binary systems

Abstract

It is shown that the emission ultraviolet doublet 2800 MgII in radio stars, actually in close binary systems, do not have chromospheric origin, but is generated in the space between the components of the system, filled by clouds or streams of two types — emission (A) and absorption (B). It is shown also that the strongly deformed or distorted forms of short wavelength halfs of emission profilesk andh MgII (Figures 1 and 4) are a result of the absorption in the intercomponent space, by cloudsB. Both qualitative and quantitative criteriums are obtained for these cloudsA andB, at which the observed forms of emission profilsk andh MgII may be explained. Particularly, the hydrogen atoms in absorption cloudsB must be ionized not strongly or be with concentrations on three orders less than in emission clouds of typeA.