Line Profiles in an Expanding Spherical Medium

Abstract

We have applied the discrete space theory of radiative with the integral operator technique to calculate the spectral line profiles formed in a spherically symmetric expanding stellar atmospheres. We calculated the source function in the comoving frame and this is employed to simulate the line profiles observed at infinity. We have considered line absorption, emission and velocities of expansion in a parametrised form. Complete redistribution of photons in the line in a two level atom is assumed with a Doppler profiles function. In all cases we have employed the equation of continuity (i.e.) 4 pie r/sup2/ rho V = constant (where rho and V are the density and velocity respectively at r) as a guide line for determining the density and the velocity of expansion. Many P Cygni type profiles are obtained. This is true particularly when velocity gradients are present in the medium. The results are similar to those of Beals (1950)