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Context. Realistic 3D time-dependent simulations of stellar near-surface convection employ the opacity binning method for efficient and accurate computation of the radiative energy exchange. The method provides several orders of magnitude…

Solar and Stellar Astrophysics · Physics 2023-07-19 A. Perdomo García , N. Vitas , E. Khomenko , M. Collados , C. Allende Prieto , I. Hubeny , Y. Osorio

We present new Rosseland and Planck mean opacity tables relevant to the shallow interiors and atmospheres of giant planets. The tables span metallicities from 0.31 to 50 times solar, temperatures from 100 - 6000 K, and pressures from 1e-6 -…

Earth and Planetary Astrophysics · Physics 2026-01-07 Louis Siebenaler , Yamila Miguel

The model for the Planck-mean dust opacity $\kappa_{P}$ given in Appendix C of the STARFORGE simulations methods paper does not extrapolate well to low radiation temperature $T_{\rm rad}$, so we provide an updated calculation suitable for…

We have developed a public code, Optab, that outputs Rosseland, Planck, and two-temperature Planck mean gas opacity tables for radiation hydrodynamics simulations in astrophysics. The code is developed for modern high-performance computing,…

Instrumentation and Methods for Astrophysics · Physics 2022-03-14 Shigenobu Hirose , Peter Hauschildt , Takashi Minoshima , Kengo Tomida , Takayoshi Sano

Rosseland mean opacity plays an important role in theories of stellar evolution and X-ray burst models. In the high-temperature regime, when most of the gas is completely ionized, the opacity is dominated by Compton scattering. Our aim here…

High Energy Astrophysical Phenomena · Physics 2017-02-01 Juri Poutanen

Due to the high quality constraints available for the Sun, we can carry out combined analyses using neutrino, spectroscopic and helioseismic observations. Such studies lay the ground for future improvements of key physical components of…

The opacity due to photodissociation of 24MgH is investigated in the atmospheres of cool stars. The lowest two electronic transitions A 2Pi -- X 2Sigma+ and B' 2Sigma+ -- X 2 Sigma+ are considered where the cross sections for the latter…

Astrophysics · Physics 2009-11-07 P. F. Weck , A. Schweitzer , P. C. Stancil , P. H. Hauschildt , K. Kirby

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

Our recent re-analysis of the solar photospheric spectra with non-local thermodynamic equilibrium (non-LTE) models resulted in higher metal abundances compared to previous works. When applying the new chemical abundances to Standard Solar…

Solar and Stellar Astrophysics · Physics 2022-09-07 Manuel A. Bautista , Maria Bergemann , Helena Carvajal Gallego , Sébastien Gamrath , Patrick Palmeri , Pascal Quinet

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

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

We present a new, publicly available, set of Los Alamos OPLIB opacity tables for the elements hydrogen through zinc. Our tables are computed using the Los Alamos ATOMIC opacity and plasma modeling code, and make use of atomic structure…

Solar and Stellar Astrophysics · Physics 2016-02-03 J. Colgan , D. P. Kilcrease , N. H. Magee , M. E. Sherrill , J. Abdallah, , P. Hakel , C. J. Fontes , J. A. Guzik , K. A. Mussack

Atomic line opacities play a crucial role in stellar astrophysics. They strongly modify the radiative transfer in stars, therefore impacting their physical structure. Ultimately, most of our knowledge of stellar population systems (stars,…

Solar and Stellar Astrophysics · Physics 2015-06-19 Lucimara Martins , Paula Coelho , Anderson Caproni , Roberto Vitoriano

We present what constraints on opacities can be derived from the analysis of stellar pulsations of BA-type main-sequence stars. This analysis consists of the construction of complex seismic models which reproduce the observed frequencies as…

Solar and Stellar Astrophysics · Physics 2019-12-03 Jadwiga Daszynska-Daszkiewicz , Przemyslaw Walczak , Alosha Pamyatnykh , Wojciech Szewczuk

Solar models through evolutionary phases of gravitational contraction, pre-main sequence and MS phases, up to current age 4.5E9 yr. and 4.57E9 yr., were studied adopting different prescriptions for the equation of state (EOS) and different…

Astrophysics · Physics 2007-05-23 M. Yildiz , N. Kiziloglu

Frequency-dependent/hybrid approaches for stellar irradiation are of primary importance in numerical simulations of massive star formation. We seek to compare outflow and accretion mechanisms in star formation simulations. We investigate…

Instrumentation and Methods for Astrophysics · Physics 2020-03-11 R. Mignon-Risse , M. González , B. Commerçon , J. Rosdahl

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…

We propose a new model for treating solid-phase photoprocesses in interstellar ice analogues. In this approach, photoionization and photoexcitation are included in more detail, and the production of electronically-excited (suprathermal)…

We implemented non-solar-scaled opacities in a simultaneous derivation of fundamental parameters and abundances. We carried out a high-precision stellar parameters and abundance determination by applying non-solar-scaled opacities and model…

Solar and Stellar Astrophysics · Physics 2018-12-05 C. Saffe , M. Flores , P. Miquelarena , F. M. Lopez , M. Jaque Arancibia , A. Collado , E. Jofre , R. Petrucci

We systematically explore the effect of the treatment of line opacity on supernova light curves. We find that it is important to consider line opacity for both scattering and absorption (i.e. thermalisation which mimics the effect of…

High Energy Astrophysical Phenomena · Physics 2020-11-11 Alexandra Kozyreva , Luke Shingles , Alexey Mironov , Petr Baklanov , Sergey Blinnikov