Spectrum Analysis of the Binary Systems with Expanding Shell Due to Stellar Wind

The ζAur-type binary system consists of a hot early type star and a late type red giant or rad supergiant with strong stellar wind,which forms an expanding gas shell surrounding the binary system.The outward motion of the shell and the orbital motion of the hot component in the shell produce the P Cygni type lines with periodic and peculiarly variable profiles in the spectra of the ζ Aur-type binary systems.The methods based on moving atmosphere theories are developed in more than this decade year.It is more accurate than other methods to determine the mass loss rates due to stellar wind.