Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-26T18:38:52.080Z Has data issue: false hasContentIssue false

Radiative Transfer Methods: new exact results for testing the accuracy of the ALI numerical method for a stellar atmosphere

Published online by Cambridge University Press:  16 November 2010

L. Chevallier*
Affiliation:
LUTH, Observatoire de Paris, Section de Meudon, 92195 Meudon, France. e-mail: [email protected]
Get access

Abstract

Tests are presented of the 1D Accelerated Lambda Iteration method, which is widely used for solving the radiative transfer equation for a stellar atmosphere. We use our ARTY code as a reference solution and tables for these tests are provided. We model a static idealized stellar atmosphere, which is illuminated on its inner face and where internal sources are distributed with weak or strong gradients. This is an extension of published tests for a slab without incident radiation and gradients. Typical physical conditions for the continuum radiation and spectral lines are used, as well as typical values for the numerical parameters in order to reach a 1% accuracy. It is shown that the method is able to reach such an accuracy for most cases but the spatial discretization has to be refined for strong gradients and spectral lines, beyond the scope of realistic stellar atmospheres models. Discussion is provided on faster methods.

Type
Research Article
Copyright
© EAS, EDP Sciences 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Amosov, A., & Dmitiev, V., 2005, MPEI Bulletin, 6 (Moscow Power EngineeringInstitute, Technical University, Krasnokazarmennaya, 14, Moscow 111250, Russia)
Auer, L.H., & Paletou, F., 1994, A&A, 284, 675
Auer, L.H., Fabiani Bendicho, P., & Trujillo Bueno, J., 1994, A&A, 292, 599 PubMed
Cannon, C.J., 1973, JQSRT, 13, 627 CrossRef
Chevallier, L., Paletou, F., & Rutily, B., 2003a, A&A, 411, 221
Chevallier, L., Paletou, F., & Rutily, B., 2003b, SF2A-2003: Semaine de l’Astrophysique Française, meeting held in Bordeaux, France, June 16-20, 2003, ed. F. Combes, D. Barret, T. Contini, & L. Pagani (EDP Sciences, Conference Series), 581
Chevallier, L., & Rutily, B., 2005, JQSRT, 91, 373 CrossRef
Fabiani Bendicho, P., Trujillo Bueno, J., & Auer, L., 1997, A&A, 324, 161
Hubeny, I., 2003, in Stellar Atmosphere Modeling, ed. I. Hubeny, D. Mihalas, & K. Werner, ASP Conf. Ser., 288, 17
Léger, L., Chevallier, L., & Paletou, F., 2007, A&A, 470, 1
Mihalas, D., 1978, Stellar Atmospheres, 2nd edn. (San Francisco: Freeman and Co)
Olson, G.L., Auer, L.H., & Buchler, J.R., 1986, JQSRT, 35, 431 CrossRef
Osses, A., & Titaud, O., 2006, EAS Publ. Ser., 18, 77 CrossRef
Paletou, F., 2001, C. R. Acad. Sci. Paris, Serie IV, t. 2, 6, 885
Paletou, F., & Léger, L., 2007, JQSRT, 103, 57 CrossRef
Quang, C., Paletou, F., & Chevallier, L., 2004, SF2A-2004: Semaine de l’Astrophysique Française, meeting held in Paris, France, June 14-18, 2004, ed. F. Combes, D. Barret, T. Contini, F. Meynadier, & L. Pagani (EDP Sciences), 317
Rutily B., “Solutions exactes de l’équation de transfert et applications astrophysiques” or “Exact solutions to the transfer equation and their application to astrophysical problems”, State Ph.D. Thesis, Université Claude Bernard-Lyon I, France, 1992
Rutily, B., & Bergeat, J., 1994, JQSRT, 51, 823 CrossRef
Rutily, B., & Chevallier, L., 2006, EAS Publ. Ser., 18, 1 CrossRef
Titaud, O., 2001, “Analyse et résolution numérique de l’équation de transfert” or “Analysis of and numerical solution to the radiative transfer equation”, Ph.D. Thesis (Univ. Jean Monnet, Saint-Etienne, France)
T. Bueno, J., & F. Bendicho, P., 1995, ApJ, 455, 646 CrossRef