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We present here a detailed calculation of opacities for Fe~XVII at the physical conditions corresponding to the base of the Solar convection zone. Many ingredients are involved in the calculation of opacities. We review the impact of each…

Solar and Stellar Astrophysics · Physics 2021-08-04 F. Delahaye , C. P. Connor , R. T. Smith , N. R. Badnell

Recent observations of rotationally supported galaxies show a tight correlation between the observed radial acceleration at every radius and the Newtonian acceleration generated by the baryonic mass distribution, the so-called radial…

Astrophysics of Galaxies · Physics 2019-07-04 Amir Ghari , Hosein Haghi , Akram Hasani Zonoozi

We have included opacity tables in our stellar evolution code that enable us to accurately model the structure of stars composed of mixtures with carbon and oxygen independently enhanced relative to solar. We present tests to demonstrate…

Astrophysics · Physics 2009-11-10 J. J. Eldridge , C. A. Tout

Codes to compute mean opacities and radiative accelerations for arbitrary chemical mixtures using the Opacity Project recently revised data have been restructured in a client--server architecture and transcribed as a subroutine library.…

We present a set of gas-phase Planck mean and Rosseland mean opacity tables applicable for simulations of star and planet formation, stellar evolution, disk modelling at various metallicities in hydrogen-rich environments. The tables are…

Solar and Stellar Astrophysics · Physics 2015-05-13 Ch. Helling , W. Lucas

An extended version of the R-matrix methodology is presented for calculation of radiative parameters for improved plasma opacities. Contrast and comparisons with existing methods primarily relying on the Distorted Wave (DW) approximation…

Solar and Stellar Astrophysics · Physics 2023-08-30 A. K. Pradhan , S. N. Nahar , W. Eissner

Convergence of the Rosseland Mean Opacity (RMO) is investigated with respect to the equation-of-state (EOS) and the number of atomic levels of iron ions prevalent at the solar radiative/convection boundary. The "chemical picture"…

Solar and Stellar Astrophysics · Physics 2023-09-22 Anil K. Pradhan

The building of a stellar structure requires knowing the Rosseland mean opacity at each layer of the model. This mean opacity is very often interpolated in pre-computed tables due to the overwhelming time to compute it from monochromatic…

Solar and Stellar Astrophysics · Physics 2021-02-10 Alain Hui-Bon-Hoa

Intending to solve the decade old problem of solar opacity, we report substantial photoabsorption uncertainty due to the effect of ion-ion correlations. By performing detailed opacity calculations of the solar mixture, we find that taking…

Solar and Stellar Astrophysics · Physics 2018-03-01 Menahem Krief , Yair Kurzweil , Alexander Feigel , Doron Gazit

The radial acceleration relation (RAR) in galaxies describes a tight empirical scaling law between the total acceleration $g_\mathrm{tot}(r)=GM_\mathrm{tot}(<r)/r^2$ observed in galaxies and that expected from their baryonic mass…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-17 Yong Tian , Keiichi Umetsu , Chung-Ming Ko , Megan Donahue , I-Non Chiu

The discrepancy between abundances computed using optical recombination lines (ORLs) and collisionally excited lines (CELs) is a major, unresolved problem with significant implications for the determination of chemical abundances throughout…

Solar and Stellar Astrophysics · Physics 2017-11-15 J. García-Rojas , R. L. M. Corradi , H. M. J. Boffin , H. Monteiro , D. Jones , R. Wesson , A. Cabrera-Lavers , P. Rodríguez-Gil

Based on the work of OPAL (Iglesias & Rogers 1996) and Alexander & Ferguson (1994), we construct a series of opacity tables for various metallicities Z=0, 0.00001, 0.00003, 0.0001, 0.0003, 0.001, 0.004, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06,…

Astrophysics · Physics 2009-11-11 Xuefei Chen , Christopher A. Tout

We have investigated how the relative elemental abundances inferred from the solar upper atmosphere are affected by uncertainties in the dielectronic recombination (DR) rate coefficients used to analyze the spectra. We find that the…

Astrophysics · Physics 2007-05-23 Daniel Wolf Savin , J. Martin Laming

The recent revision of the solar chemical composition (Asplund, Grevesse and Sauval 2005)is characterized by about 40 per cent decrease of C, N, O, Ne, Ar abundances and by 20 percent decrease of Fe and some other metal abundances. We…

Astrophysics · Physics 2009-11-13 A. A. Pamyatnykh , W. Ziomek

We show that standard solar models are in good agreement with the helioseismologically determined sound speed and density as a function of solar radius, the depth of the convective zone, and the surface helium abundance, as long as those…

Astrophysics · Physics 2011-09-29 John N. Bahcall , Sarbani Basu , Marc Pinsonneault , Aldo M. Serenelli

We carry out a test of the radial acceleration relation (RAR) for galaxy clusters from two different catalogs compiled in literature, as an independent cross-check of two recent analyses, which reached opposite conclusions. The datasets we…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-29 S. Pradyumna , Sajal Gupta , Sowmya Seeram , Shantanu Desai

Aimed at solving the outstanding problem of solar opacity, and radiation transport plasma models in general, we report substantial photoabsorption in the high-energy regime due to atomic core photo-excitations not heretofore considered. In…

Solar and Stellar Astrophysics · Physics 2016-06-22 Sultana N. Nahar , Anil K. Pradhan

Tables of mean opacities are often used to compute the transfer of radiation in a variety of astrophysical simulations from stellar evolution models to proto-planetary disks. Often tables, such as Ferguson et al. (2005), are computed with a…

The calculation of line widths constitutes theoretical and computational challenges in the calculation of opacities of hot dense plasmas. Opacity models use line broadening approximations that are untested at stellar interior conditions.…

Solar and Stellar Astrophysics · Physics 2016-06-22 M. Krief , A. Feigel , D. Gazit

Radiation reaction effects on ion acceleration in laser foil interaction are investigated via analytical modeling and multi-dimensional particle-in-cell simulations. We find the radiation effects are important in the area where some…

Plasma Physics · Physics 2009-09-29 Min Chen , Alexander Pukhov , Tong-Pu Yu , Zheng-Ming Sheng