A new nonlocal thermodynamical equilibrium radiative transfer method for cool stars Method and numerical implementation
Lambert, Julien LU ; Josselin, E. ; Ryde, Nils LU
and Faure, A.
(2015)
In Astronomy & Astrophysics
580.
- Abstract
- Context. The solution of the nonlocal thermodynamical equilibrium (non-LTE) radiative transfer equation usually relies on stationary iterative methods, which may falsely converge in some cases. Furthermore, these methods are often unable to handle large-scale systems, such as molecular spectra emerging from, for example, cool stellar atmospheres. Aims. Our objective is to develop a new method, which aims to circumvent these problems, using nonstationary numerical techniques and taking advantage of parallel computers. Methods. The technique we develop may be seen as a generalization of the coupled escape probability method. It solves the statistical equilibrium equations in all layers of a discretized model simultaneously. The numerical... (More)
- Context. The solution of the nonlocal thermodynamical equilibrium (non-LTE) radiative transfer equation usually relies on stationary iterative methods, which may falsely converge in some cases. Furthermore, these methods are often unable to handle large-scale systems, such as molecular spectra emerging from, for example, cool stellar atmospheres. Aims. Our objective is to develop a new method, which aims to circumvent these problems, using nonstationary numerical techniques and taking advantage of parallel computers. Methods. The technique we develop may be seen as a generalization of the coupled escape probability method. It solves the statistical equilibrium equations in all layers of a discretized model simultaneously. The numerical scheme adopted is based on the generalized minimum residual method. Results. The code has already been applied to the special case of the water spectrum in a red supergiant stellar atmosphere. This demonstrates the fast convergence of this method, and opens the way to a wide variety of astrophysical problems. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/8080488
- author
- Lambert, Julien
LU
; Josselin, E.
; Ryde, Nils
LU
and Faure, A.
- organization
- publishing date
- 2015
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- radiative transfer, stars: atmospheres, methods: numerical
- in
- Astronomy & Astrophysics
- volume
- 580
- article number
- A50
- publisher
- EDP Sciences
- external identifiers
-
- wos:000360020200050
- scopus:84938304819
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361/201322852
- project
- VR-projektbidrag: Infraröd spektroskopi - ett nytt fönster mot galaktisk astronomi
- Carl-TryggerStiftelse: Water on Stars
- language
- English
- LU publication?
- yes
- id
- 77ba4d29-c448-423c-aa2d-52c6b14922a8 (old id 8080488)
- date added to LUP
- 2016-04-01 13:53:32
- date last changed
- 2022-12-11 20:50:43
@article{77ba4d29-c448-423c-aa2d-52c6b14922a8,
abstract = {{Context. The solution of the nonlocal thermodynamical equilibrium (non-LTE) radiative transfer equation usually relies on stationary iterative methods, which may falsely converge in some cases. Furthermore, these methods are often unable to handle large-scale systems, such as molecular spectra emerging from, for example, cool stellar atmospheres. Aims. Our objective is to develop a new method, which aims to circumvent these problems, using nonstationary numerical techniques and taking advantage of parallel computers. Methods. The technique we develop may be seen as a generalization of the coupled escape probability method. It solves the statistical equilibrium equations in all layers of a discretized model simultaneously. The numerical scheme adopted is based on the generalized minimum residual method. Results. The code has already been applied to the special case of the water spectrum in a red supergiant stellar atmosphere. This demonstrates the fast convergence of this method, and opens the way to a wide variety of astrophysical problems.}},
author = {{Lambert, Julien and Josselin, E. and Ryde, Nils and Faure, A.}},
issn = {{0004-6361}},
keywords = {{radiative transfer; stars: atmospheres; methods: numerical}},
language = {{eng}},
publisher = {{EDP Sciences}},
series = {{Astronomy & Astrophysics}},
title = {{A new nonlocal thermodynamical equilibrium radiative transfer method for cool stars Method and numerical implementation}},
url = {{http://dx.doi.org/10.1051/0004-6361/201322852}},
doi = {{10.1051/0004-6361/201322852}},
volume = {{580}},
year = {{2015}},
}