Updated opacities from the Opacity Project

By N. Badnell, M. Bautista, K. Butler, F. Delahaye, C. Mendoza, P. Palmeri, C. Zeippen, M. Seaton. 2004

308 citations recorded by the source corpus.

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 updated opacities from the Opacity Project (OP). A number of other improvements on earlier work have also been included. Rosseland-mean opacities from the OP are compared with those from OPAL. Differences of 5-10 per cent occur. The OP gives the 'Z-bump', at log(T) 5.2, to be shifted to slightly higher temperatures. The opacities from the OP, as functions of temperature and density, are smoother than those from OPAL. The accuracy of the integrations used to obtain mean opacities can depend on the frequency mesh used. Tests involving variation of the numbers of frequency points show that for typical chemical mixtures the OP integrations are numerically correct to within 0.1 per cent. The accuracy of the interpolations used to obtain mean opacities for any required values of temperature and density depends on the temperature-density meshes used. Extensive tests show that, for all cases of practical interest, the OP interpolations give results correct to better than 1 per cent. Prior to a number of recent investigations which have indicated a need for downward revisions in the solar abundances of oxygen and other elements, there was good agreement between properties of the Sun deduced from helioseismology and from stellar evolution models calculated using OPAL opacities. The revisions destroy that agreement. In a recent paper, Bahcall et al. argue that the agreement would be restored if opacities for the regions of the Sun with 2 × 106T 5 × 106 K (0.7-0.4 R) were larger than those given by OPAL by about 10 per cent. In the region concerned, the present results from the OP do not differ from those of OPAL by more than 2.5 per cent.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/340bcc945b03d690fc99241e880084431793824a

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Citations in the corpus

Improvements to stellar structure models, based on a grid of 3D convection simulations. II. Calibrating the mixing-length formulation (2014, background): “…2002; Militzer & Hubbard 2013) and opacities (Kurucz 1992b; Rogers & Iglesias 1992; Alexander & Ferguson 1994; Seaton 1995; Iglesias & Rogers 1996; Badnell et al. 2005; Ferguson et al. 2007), by far the most uncertain aspects of stellar models are associated with dynamical phenomena:…”
10,000 Standard Solar Models: A Monte Carlo Simulation (2005, methodology): “Only elements accounted for in the Opacity Project radiative opacity calculations are given (Badnell et al. 2005).”
Helioseismology and Solar Abundances (2007, methodology): “Badnell et al. (2005) calculated OP opacities with more elements in the heavy-element mixture, and a comparison between models constructed with these OP opacities and those constructed with OPAL opacities showed that the difference between OP and OPAL opacities near the base of the convection zone…”
Evolution of thermally pulsing asymptotic giant branch stars - I. The COLIBRI code (2013, methodology): “…Pg and temperature T ), makes direct calls to one of two opacity codes, depending on the temperature: • The Opacity Project1 (OP) (OP; Seaton 2005; Badnell et al. 2005) for 4.2 < log T 6 8.0; 1 We have used the OPCD 3.3 open-source package available at the WEB page…”
A NICER View of PSR J0030+0451: Millisecond Pulsar Parameter Estimation (2019, methodology): “While opacity tables for partially ionized matter exist (Iglesias & Rogers 1996; Badnell et al. 2005; Colgan et al. 2016), they do not cover the full range of energies and temperatures needed for our analysis.”
A UNIFIED REPRESENTATION OF GAS-PHASE ELEMENT DEPLETIONS IN THE INTERSTELLAR MEDIUM (2009, result): “…& Przybilla 2008a,b) but are inconsistent with the results from helioseismological studies of the sound speed and depth of the convection zone inside the Sun (Bahcall et al. 2005a,b; Antia & Basu 2005, 2006), which favor the earlier abundances when the opacities are computed (Badnell et al. 2005).”
Bump Cepheids in the Magellanic Clouds: Metallicities, the Distances to the LMC and SMC, and the Pulsation-Evolution Mass Discrepancy (2006, background): “Largely in response to this mass discrepancy, more detailed modelling of opacities was undertaken by the OPAL (Rogers & Iglesias 1992) and Opacity Projects (Seaton et al. 1994).”
The Stagger-grid: A grid of 3D stellar atmosphere models - I. Methods and general properties (2013, background): “These calculations are improvements over those forming thebasis for the OP opacities6 (Badnell et al. 2005).”
A New Generation of Standard Solar Models (2016, methodology): “Updated calculations (Badnell et al. 2005) by the Opacity Project have led the way, followed by OPAS (Blancard et al. 2012; Mondet et al. 2015), STAR (Krief et al. 2016b) and a new version of OPLIB, the opacities from Los Alamos (Colgan et al. 2016).”
Sub-surface convection zones in hot massive stars and their observable consequences (2009, background): “The reality of the iron opacity bump, as predicted by various groups (e.g., Iglesias et al. 1992; Badnell et al. 2005), is unambiguous.”
OPACITIES AND SPECTRA OF THE r-PROCESS EJECTA FROM NEUTRON STAR MERGERS (2013, methodology): “This code was used previously to calculate data up to Ni for the updated opacities of the Opacity Project (Badnell et al. 2005).”