A. Peraiah
57, 4th Cross 36th Main, B T M 1st Stage, Madiwala-Dollar
Scheme, Bangalore 560 068, India
Abstract. We studied the influence of high veolcities of expansion on resonance line radiation by taking into account of aberration and advection. We used an angle averaged redistribution function RII in spherically symmetric media. Three types of media are considered. These are: (1) purely scattering medium (2) partly scattering and emission from continuum medium and (3) partly scattering and continuum and line emission medium. The spherical shells that are being used have thicknesses equal to 2, 10 and 100 times the stellar radii. The radiation field is shown in terms of teh source functions. Computations are performed in the comoving frame of the gas and the line profiles are calculated at the observer's point at infinity. The line profiles computed in the first type of medium show P Cygni characteristics and those computed in the second and third type of media show central emission and self absorption.
Keywords: radiative transfer - line formation - stellar atmospheres - aberration - advection - redistribution function.