Curvature effects in extended stellar atmospheres-absorption and scattering

Abstract

The effects of curvature in an atmosphere with pure absorption are investigated. Numerical solution of the transfer equation was obtained in the framework of the Discrete Space Theory of Radiative Transfer. Two cases were considered: the atmosphere is irradiated at the bottom and there is no incident radiation at the top of the atmosphere; no radiation is incident on either side of the atmosphere. It was found that the thermal sources inside the atmosphere dominantly influence the emergent radiation, and this is very much so in the spherical case and for large optical thickness. The emergent luminosities increase wtth the geometrlcal thickness, although the emergent specific intensities are reduced; the former seems to be because of the larger surfuce area, and the latter seems to be because of the effects of curvature. (8 figures) (auth)