Boundary layer conditions for the transport of radiation in stars
Abstract
An expansion technique used by Larsen et al. (1983) for describing coherent scattering is applied to characterizing an outer thermal boundary condition for radiation transport in stellar interiors. Modifications are introduced to cover conditions of non-gray radiative equilibrium, which is analyzed asymptotically. An expansion parameter is defined in terms of coupled transfer and energy equations and carried out to first order to obtain a ratio of the photon free path to the stellar characteristic dimension. The ratio provides a scale for the space variable with which a singular perturbation problem is solved for interior and boundary conditions, the latter being in the stellar atmosphere and the sum of the interior solution and the boundary layer correction. A Robin boundary condition results which is only 5 percent higher in temperature than the interior in the case of a gray opacity coefficient.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 1984
- Bibcode:
- 1984A&A...140...57F
- Keywords:
-
- Boundary Conditions;
- Boundary Layer Equations;
- Radiative Transfer;
- Stellar Radiation;
- Stellar Temperature;
- Asymptotic Methods;
- Equilibrium Equations;
- Stellar Interiors;
- Stellar Structure;
- Surface Temperature;
- Astrophysics