Reference : Numerical applications to radiative transfer in expanding envelopes - The two-level a...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/17727
Numerical applications to radiative transfer in expanding envelopes - The two-level atom model
English
Surdej, Jean mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS) >]
1978
Astronomy and Astrophysics
EDP Sciences
66
45-55
Yes (verified by ORBi)
International
0004-6361
1432-0746
Les Ulis
France
[en] RADIATIVE TRANSFER ; STELLAR ENVELOPES ; STELLAR SPECTRA ; ACCELERATION (PHYSICS) ; EMISSION SPECTRA ; EQUILIBRIUM EQUATIONS ; GRAPHS (CHARTS) ; RADIAL VELOCITY ; ATOMIC ENERGY LEVELS
[en] The escape probability method developed by Sobolev (1947) is applied to the case of a two-level atom. The numerical applications are based on a previous work concerning a general theory of spectral-line formation in outward-accelerating and outward-decelerating stellar envelopes. Only the radiative exchanges occurring between the atomic levels are considered, and the statistical-equilibrium equations are solved rigorously in the cases of a transparent medium at rest, an outward-accelerating envelope, and an outward-decelerating envelope. The population of the atomic levels are compared for different physical conditions in each case. It is shown numerically that in the case of an outward-decelerating envelope the contribution of distant atoms to the mean intensity of line radiation appreciably enhances the degree of excitation throughout the envelope.
Researchers ; Professionals
http://hdl.handle.net/2268/17727
http://esoads.eso.org/abs/1978A%26A....66...45S
The authors thank EDP Sciences for their deposit authorization

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