Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· On-line Data
· References in the article
· Citations to the Article (367) (Citation History)
· Refereed Citations to the Article
· Associated Articles
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Opacities for Stellar Envelopes
Authors:
Seaton, M. J.; Yan, Y.; Mihalas, D.; Pradhan, A. K.
Publication:
R.A.S. MONTHLY NOTICES V.266, NO. 4/FEB15, P. 805, 1994 (MNRAS Homepage)
Publication Date:
02/1994
Origin:
KNUDSEN
MNRAS Keywords:
atomic processes - radiative transfer - stars: interiors
Bibliographic Code:
1994MNRAS.266..805S

Abstract

We define stellar envelopes to be those regions of stellar interiors in which atoms exist and are not markedly perturbed by the plasma environment. Availability of accurate and extensive atomic data is a prime requirement for the calculation of envelope opacities. For envelopes we adopt the criterion of mass density p < 0.01 ρ≥g cm-3.

We present radiative Rosseland mean opacities for envelopes obtained using atomic data calculated in an international collaboration referred to as the Opacity Project, or OP. Equations of state are calculated using an occupation-probability formalism. To a good approximation, ionization equilibria and level populations in envelopes depend only on the temperature T and electron density Ne and are insensitive to chemical mixtures. Monochromatic opacities for all abundant chemical elements are therefore calculated on a grid of (T, Ne) values and are archived. Rosseland mean opacities are then readily calculated for any chemical mixture. Tables of Rosseland means, for any required mixtures and as functions of ρ and T, are available on request in computer-readable form.

The present, op, results are compared with those from another recent study, referred to as OPAL, by C. A. Iglesias and F. A. Rogers at the Lawrence Livermore National Laboratory. The agreement between the OP and OPAL calculations is generally good, although there are some differences. Both calculations give results larger than those obtained in earlier work, by factors of up to 3 or more.

Associated Articles

Source Paper     Catalog Description     Catalog Description    

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences


More Article Retrieval Options

HELP for Article Retrieval
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints