A Radiative Transfer Calculation Using R(III) in an Expanding Spherically Symmetric Stellar Atmosphere

Abstract

With the availability of very high-resolution stellar spectra, even small differences between line profiles resulting from complete redistribution and partial frequency redistribution may be important in the quantitative analysis of stellar spectra. A differentially expanding and spherically symmetric stellar envelope is considered in order to study the effects of the angle-averaged partial frequency redistribution function of the star, assuming a two-level atomic model. The differences between the emergent mean intensity profiles resulting from complete redistribution and the angle-averaged R III are found to be much smaller in expanding spherically symmetric stellar atmospheres than has been reported previously for plane-parallel atmospheres.