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Partially coherent scattering in stellar chromospheres. II - The first-order escape probability method. III - A second-order escape probability methodApproximate analytic expressions are derived for resonance-line wing diagnostics, accounting for frequency redistribution effects, for homogeneous slabs, and slabs with a constant Planck function gradient. Resonance-line emission profiles from a simplified conceptual standpoint are described in order to elucidate the basic physical parameters of the line-forming layers prior to the performance of detailed numerical calculations. An approximate analytic expression is derived for the dependence on stellar surface gravity of the location of the Ca II and Mg II resonance-line profile peaks. An approximate radiative transfer equation using generalized second-order escape probabilities, applicable even in the presence of nearly coherent scattering in the damping wings of resonance lines, is derived. Approximate analytic solutions that can be applied in special regimes and achieve good agreement with accurate numerical results are found.
Document ID
19920054154
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Gayley, K. G.
(Joint Institute for Laboratory Astrophysics Boulder, CO, United States)
Date Acquired
August 15, 2013
Publication Date
May 10, 1992
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 390
Issue: 2 Ma
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
92A36778
Funding Number(s)
CONTRACT_GRANT: NAGW-2568
Distribution Limits
Public
Copyright
Other

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