Models of the P Cygni envelope. An analysis of the formation of hydrogen spectral lines

Six kinematic models of the P Cygni envelope have been analyzed. It appeared that only the model with three zones can explain all the observed features of Balmer-line profiles. The thermodynamic structure of the models, as the base for profile calculation, has been determined from statistical equilibrium equations for energy level populations of the hydrogen atom, and from the equation of thermal balance of free electrons. The dependence of the kinetic temperature on the radial distance in a three zone model can explain also the existence of low excitation metallic (FeII, NiII, MnII) spectral lines found mainly in the ultraviolet spectral region. The scattering of spectral line radiation by free electrons has been checked with the help of the method of iterative determination of scattering source function. The emission wings of the Hsub(α)-line can be formed by scattering process in the expanding envelope with three zone model structure