Updated Opal Opacities

TLDR

Reexamination of astrophysical opacities has removed major discrepancies between observations and theory, enabling more detailed stellar model tests, while studies show model results are sensitive to modest opacity changes. The study aims to update opacity databases with recent physics improvements, refined element abundances, and other relevant factors. The updated opacities incorporate improved physics, numerical procedures, and corrections, provide tables enabling accurate interpolation over density, temperature, and elemental mass fractions, allow for various metal distributions, and are compared to other studies. The updated OPAL Rosseland mean opacities show increases up to 20 % for Population I stars from adding 19 metals, with other changes below 10 %, and extend the temperature and density coverage. Published in The Astrophysical Journal (June 1996), DOI 10.1086/177381.

Abstract

view Abstract Citations (2552) References (48) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Updated Opal Opacities Iglesias, Carlos A. ; Rogers, Forrest J. Abstract The reexamination of astrophysical opacities has eliminated gross discrepancies between a variety of observations and theoretical calculations; thus allowing for more detailed tests of stellar models. A number of such studies indicate that model results are sensitive to modest changes in the opacity. Consequently, it is desirable to update available opacity databases with recent improvements in physics, refinements of element abundance, and other such factors affecting the results. Updated OPAL Rosseland mean opacities are presented. The new results have incorporated improvements in the physics and numerical procedures as well as corrections. The main opacity changes are increases of as much as 20% for Population I stars due to the explicit inclusion of 19 metals (compared to 12 metals in the earlier calculations) with the other modifications introducing opacity changes smaller than 10%. In addition, the temperature and density range covered by the updated opacity tables has been extended. As before, the tables allow accurate interpolation in density and temperature as well as hydrogen, helium, carbon, oxygen, and metal mass fractions. Although a specific metal composition is emphasized, opacity tables for different metal distributions can be made readily available. The updated opacities are compared to other work. Publication: The Astrophysical Journal Pub Date: June 1996 DOI: 10.1086/177381 Bibcode: 1996ApJ...464..943I Keywords: ATOMIC DATA; ATOMIC PROCESSES; STARS: INTERIORS full text sources ADS |