Low-Temperature Opacities

By J. Ferguson, D. Alexander, F. Allard, Travis S. Barman, J. Bodnarik, Peter Hauschildt, Amanda Heffner-Wong, A. Tamanai. 2005

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Previous computations of low-temperature Rosseland and Planck mean opacities from Alexander & Ferguson are updated and expanded. The new computations include a more complete equation of state (EOS) with more grain species and updated optical constants. Grains are now explicitly included in thermal equilibrium in the EOS calculation, which allows for a much wider range of grain compositions to be accurately included than was previously the case. The inclusion of high-temperature condensates such as Al2O3 and CaTiO3 significantly affects the total opacity over a narrow range of temperatures before the appearance of the first silicate grains. The new opacity tables are tabulated for temperatures ranging from 30,000 to 500 K with gas densities from 10-4 to 10-19 g cm-3. Comparisons with previous Rosseland mean opacity calculations are discussed. At high temperatures, the agreement with OPAL and Opacity Project is quite good. Comparisons at lower temperatures are more divergent as a result of differences in molecular and grain physics included in different calculations. The computation of Planck mean opacities performed with the opacity sampling method is shown to require a very large number of opacity sampling wavelength points; previously published results obtained with fewer wavelength points are shown to be significantly in error. Methods for requesting or obtaining the new tables are provided.

Subfields: Atomic and Molecular Physics, and Optics, Geophysics, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/d8e8839663414fd4fb2c6fd686ea23eef2cf7490

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Citations in the corpus

NONSTEADY ACCRETION IN PROTOSTARS (2008, background): “Our understanding of opacity sources (especially dust and molecular line spectra) has improved both observationally and theoretically since then (Alexander & Ferguson 1994; Ferguson et al. 2005; D’Alessio et al. 1998, 2001; Zhu et al. 2007).”
CESAM: a free code for stellar evolution calculations (2008, methodology): “Two sets of low temperature opacities have been used: the Alexander & Ferguson (1994) tables given for the Grevesse & Noels (1993) solar mixture and the Ferguson et al. (2005) tables given for the new solar mixture derived by Asplund et al. (2005) (see below).”
Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing (2016, neutral): “…1H, 3He, 4He, 12C, 13C, 13N, 14N, 15N, 14O, 15O, 16O, 17O, 18O, 17F, 18F, 19F,18Ne, 19Ne, 20Ne, 22Mg and 24Mg. Radiative opacities are taken from Ferguson et al. (2005) for 2.7 ≤ log T ≤ 4.5 and OPAL (Iglesias & Rogers 1993, 1996) for 3.75 ≤ log T ≤ 8.7 and conductive opacities are adopted from…”
MAKE SUPER-EARTHS, NOT JUPITERS: ACCRETING NEBULAR GAS ONTO SOLID CORES AT 0.1 AU AND BEYOND (2014, methodology): “2.7 ≤ log T ≤ 3.6 and log ρ ≥ −6: tabulated in Ferguson et al. (2005), with supplemental data calculated by J. Ferguson (2013, personal communication) 4. log T < 2.7 and log ρ < −6: κ = κ(log T = 2.7, log ρ = −6) (constant extrapolation) 5.”
Evolution and fate of very massive stars (2013, neutral): “(iv) Opacities is taken from OPAL (Iglesias & Rogers 1996) and completed with low temperature opacities from Ferguson et al. (2005) adapted for the high Ne abundance.”
Spectral models for solar-scaled and α-enhanced stellar populations (2007, methodology): “Throughout this paper we are using Rosseland opacity tables from the OPAL-website2 (Iglesias & Rogers 1996) for high temperatures together with low-temperature molecular opacity tables calculated by one of us (JF), employing the code by Ferguson et al. (2005).”
RADIATION MAGNETOHYDRODYNAMIC SIMULATIONS OF PROTOSTELLAR COLLAPSE: PROTOSTELLAR CORE FORMATION (2012, methodology): “Therefore, we connect the tables of Semenov et al. (2003) and Ferguson et al. (2005) at the temperature where all the dust components evaporate.”
Ages and fundamental properties of Kepler exoplanet host stars from asteroseismology (2015, background): “…of State (Rogers, Swenson & Iglesias 1996; Rogers & Nayfonov 2002), OPAL opacities for high temperatures (Iglesias & Rogers 1996) and those of Ferguson et al. (2005) for low temperatures, the NACRE compilation of nuclear reaction rates (Angulo et al. 1999) including the updated 14N(p, γ)15O…”
Revisiting the axion bounds from the Galactic white dwarf luminosity function (2014, background): “Conductive opacities are those of [31] while radiative opacities are those of the OPAL project [32] complemented at low temperatures by the molecular opacities produced by [33].”
Super and massive AGB stars - IV. Final fates - Initial to final mass relation (2014, methodology): “Opacities are from OPAL (Iglesias & Rogers 1996) and for the majority of models we use the compilation of Ferguson et al. (2005) for the low temperature regime.”
Thermohaline instability and rotation-induced mixing I. Low- and intermediate-mass solar metallicity stars up to the end of the AGB (2010, methodology): “We use the OPAL opacity tables (Iglesias & Rogers 1996) for T > 8000 K that account for C and O enrichments, and the Ferguson et al. (2005) data at lower temperatures.”
A New Generation of Standard Solar Models (2016, background): “Atomic opacities are from OP Badnell et al. (2005) and are complemented at low temperatures with molecular opacities from Ferguson et al. (2005).”
The Pisa pre-main sequence tracks and isochrones - A database covering a wide range of Z, Y, mass, and age values (2011, methodology): “For lower temperatures, characteristic of theouter stellar regions, we used the radiative opacity of Ferguson et al. (2005) (hereafter F05)5, which include an accurate description of the molecular absorptions; indeed for T≤ 4500 K, hence for low-mass stars, molecules become the main source of…”
YREC: the Yale rotating stellar evolution code (2007, background): “At low temperatures (log T < 4.1) opacities are obtained from the tables provided by Ferguson et al. (2005).”
Thermohaline instability and rotation-induced mixing - III. Grid of stellar models and asymptotic asteroseismic quantities from the pre-main sequence up to the AGB for low- and intermediate-mass stars of various metallicities (2012, methodology): “At lower temperature (T < 8000 K), we use the atomic and molecular opacities given by Ferguson et al. (2005).”