On the Use of Variable Eddington Factors in Non-LTE Stellar Atmospheres Computations

Abstract

It is shown that by use of variable Eddington factors, the accuracy of difference-equation solutions of transfer problems may be greatly improved with only small additional computational effort. It is found that a direct iterative calculation of the Eddington factors leads to a strongly convergent procedure. The resulting set of equations is of wide applicability to problems involving non-coherent radiative transfer. The method is illustrated by application to the classical grey problem, and to a non-L TE stellar atmospheres computation.