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Monochromatic opacities from the Opacity Project (OP) (Seaton et al.) have been augmented by hitherto missing inner-shell contributions (Badnell & Seaton). OP Rosseland-mean opacities are compared with results from OPAL (Iglesias & Rogers)…

Astrophysics · Physics 2009-11-10 M. J. Seaton , N. R. Badnell

Using the code AUTOSTRUCTURE, extensive calculations of inner-shell atomic data have been made for the chemical elements He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Cr, Mn, Fe and Ni. The results are used to obtain up-dated opacities from…

Stellar seismology appears more and more as a powerful tool for a better determination of the fundamental properties of solar-type stars. However the particular case of Sun is still challenging. The helioseismic sound speed determination…

Evolutionary models have been calculated for Pop II stars of 0.5 to 1.0$M_\odot$ from the pre-main-sequence to the lower part of the giant branch. Rosseland opacities and radiative accelerations were calculated taking into account the…

Astrophysics · Physics 2008-11-26 O. Richard , G. Michaud , J. Richer , S. Turcotte , S. Turck-Chieze , Don A. VandenBerg

Atomic diffusion with radiative levitation is a major transport process to consider to explain abundance anomalies in Am stars. Radiative accelerations vary from one species to another, yielding different abundance anomalies at the stellar…

Solar and Stellar Astrophysics · Physics 2024-11-20 Alain Hui-Bon-Hoa

For high temperatures and densities, stellar opacities obtained from the Opacity Project (OP) were smaller than those obtained from the OPAL project. Iglesias and Rogers [Ap.J. v443, 469 (1995)] suggested that the discrepancy was due to the…

Astrophysics · Physics 2009-11-10 N. R. Badnell , M. J. Seaton

The chemical element nickel is of particular interest in stellar physics. In the layers in which the Fe-peak elements dominate the mean opacity (the so-called Z-bump), Ni is the second contributor to the Rosseland opacity after iron,…

Solar and Stellar Astrophysics · Physics 2022-02-09 A. Hui-Bon-Hoa , J. -C. Pain , O. Richard

We construct solar models with the newly calculated radiative opacities from the Opacity Project (OP) and recently determined (lower) heavy element abundances. We compare results from the new models with predictions of a series of models…

Astrophysics · Physics 2009-11-10 John N. Bahcall , Aldo M. Serenelli , Sarbani Basu

We attempt to produce low temperature opacity data incorporating the effects of varied abundances of the elements carbon and nitrogen. For our temperature range of interest, molecules represent the dominant opacity source. Our dataset…

Astrophysics · Physics 2009-11-13 Michael T. Lederer , Bernhard Aringer

The revision of the standard Los Alamos opacities in the 1980-1990s by a group from the Lawrence Livermore National Laboratory (OPAL) and the Opacity Project (OP) consortium was an early example of collaborative big-data science, leading to…

Solar and Stellar Astrophysics · Physics 2018-05-22 Claudio Mendoza

The radial acceleration relation (RAR) links observed and baryonic accelerations, and is best established in rotation curves of late-type galaxies. Pulsar timing, which measures line-of-sight (LOS) differential accelerations between the Sun…

Astrophysics of Galaxies · Physics 2026-05-08 Tariq Yasin , Harry Desmond

Chemical element transport processes are among the crucial physical processes needed for precise stellar modelling. Atomic diffusion by gravitational settling nowadays is usually taken into account, and is essential for helioseismic…

Solar and Stellar Astrophysics · Physics 2018-10-03 M. Deal , G. Alecian , Y. Lebreton , M. J. Goupil , J. P. Marques , F. LeBlanc , P. Morel , B. Pichon

A new opacity model based on the Super-Transition-Array (STA) method for the calculation of monochromatic opacities of local thermodynamic equilibrium plasmas, was developed. The atomic code, named STAR (STA-Revised), is described and used…

Solar and Stellar Astrophysics · Physics 2016-04-20 M. Krief , A. Feigel , D. Gazit

In the framework of the present phase -- IPOPv2 -- of the international Opacity Project (OP), a new web service has been implemented based on the latest release of the OP opacities. The user may construct online opacity tables to be…

Solar and Stellar Astrophysics · Physics 2016-02-17 F. Delahaye , C-M. Zwolf , C. Zeippen , C. Mendoza

Opacity is an important ingredient of the evolution of stars. The calculation of opacity coefficients is complicated by the fact that the plasma contains partially ionized heavy ions that contribute to opacity dominated by H and He. Up to…

Seismology of stars is strongly developing. To address this question we have formed an international collaboration OPAC to perform specific experimental measurements, compare opacity calculations and improve the opacity calculations in the…

The radial acceleration relation (RAR) of late-type galaxies relates their dynamical acceleration, $g_\text{obs}$, to that sourced by baryons alone, $g_\text{bar}$, across their rotation curves. Literature fits to the RAR have fixed the…

Astrophysics of Galaxies · Physics 2024-02-27 Harry Desmond

We combine kinematic and gravitational lensing data to construct the Radial Acceleration Relation (RAR) of galaxies over a large dynamic range. We improve on previous weak-lensing studies in two ways. First, we compute stellar masses using…

Astrophysics of Galaxies · Physics 2024-04-10 Tobias Mistele , Stacy McGaugh , Federico Lelli , James Schombert , Pengfei Li

We present a set of 1194 Type-1 Rosseland-mean opacity tables for four different metallicity mixtures. These new Los Alamos OPLIB atomic radiative opacity tables are an order of magnitude larger in number than any previous opacity table…

All monochromatic opacity data from the Opacity Project (OP), together with all codes required for the calculation of mean opacities and radiative accelerations for any required chemical mixture, temperature and mass-density, are being put…

Astrophysics · Physics 2009-11-10 M. J. Seaton
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