Special Issue "Atomic and Molecular Opacity Data for Astrophysics"

A special issue of Atoms (ISSN 2218-2004).

Deadline for manuscript submissions: 31 March 2018

Special Issue Editor

Guest Editor
Dr. Jean-Christophe Pain

Commissariat à l’Energie Atomique (CEA), DAM, DIF, F-91297 Arpajon, France
E-Mail
Interests: helio- and asteroseismology; stellar spectra; multicharged-ion plasmas; local and non-local thermodynamic equilibrium plasmas; radiative opacity; atomic processes in stellar interiors and envelopes; photo-ionization; photo-excitation; inverse Bremsstrahlung; databases; radiative transfer; radiative acceleration; molecular opacity

Special Issue Information

Dear Colleagues,

The revision of the standard Los Alamos opacities thirty years ago by the Lawrence Livermore National Laboratory (OPAL) and the Opacity Project (OP) teams was an early example of collaborative big-data science, yielding reliable computed quantities (spectral and mean opacities, radiative accelerations) that were widely used to investigate many astrophysical topics. The precision of the calculated opacities is a key point of comparisons between theory, laboratory (laser or Z-pinch) plasma spectroscopy experiments, and stellar observations in different frameworks: Standard Solar Model (SSM); helio- and astero-seismology (for instance of Beta Cephei-type pulsating stars); non-local thermodynamic-equilibrium 3D hydrodynamic photospheric modeling; nuclear reaction rates, solar neutrino detections, etc. In this context, the recent revision of the solar photospheric metal abundances in 2005 spoiled the agreement between the helioseismic indicators (depth of the convection zone, sound-speed profile, and helium surface abundance) and the SSM predictions, agreement that could be recovered with a substantial opacity increase.

Spectroscopic observations of brown dwarfs and extrasolar giant planets (hot Jupiter stars and super-Earths) in the infrared to the ultraviolet ranges are now possible. The model atmospheres can be tested for atmospheric temperatures (100–3000 K) and pressures (10-6–100 atm) at which many molecules reside. Molecular opacities (accounting for rotational-vibrational and electronic bound-free, bound-bound, free-free, and collision-induced transitions) for alkali metals, iron, heavy metal oxides, metal hydrides, H2, CO, H2O, N2, CH4, NH3, CO2, HCN, H2S, PH3, etc., needed to simulate astronomical observations, can be obtained from laboratory measurements or ab initio calculations.

This Special Issue of Atoms will highlight the need for continuing research on the atomic and molecular opacity data for astrophysics. It will present recent theoretical and experimental works, as well as investigations in astrophysics where opacities have been used as a tool to investigate physical properties of celestial objects.

Dr. Jean-Christophe Pain
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Atoms is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 350 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • stellar spectra
  • Active-Galactic-Nuclei spectra
  • interstellar spectra
  • asteroseismology
  • pulsating stars
  • beta Cephei
  • Standard Solar Model
  • tachocline
  • exoplanets
  • extragalactic objects
  • laboratory plasma
  • Z-pinch
  • lasers
  • atomic and molecular opacity

Published Papers (1 paper)

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Research

Open AccessFeature PaperArticle Detailed Opacity Calculations for Astrophysical Applications
Atoms 2017, 5(2), 22; doi:10.3390/atoms5020022
Received: 30 January 2017 / Revised: 2 May 2017 / Accepted: 16 May 2017 / Published: 30 May 2017
PDF Full-text (4718 KB) | HTML Full-text | XML Full-text
Abstract
Nowadays, several opacity codes are able to provide data for stellar structure models, but the computed opacities may show significant differences. In this work, we present state-of-the-art precise spectral opacity calculations, illustrated by stellar applications. The essential role of laboratory experiments to check
[...] Read more.
Nowadays, several opacity codes are able to provide data for stellar structure models, but the computed opacities may show significant differences. In this work, we present state-of-the-art precise spectral opacity calculations, illustrated by stellar applications. The essential role of laboratory experiments to check the quality of the computed data is underlined. We review some X-ray and XUV laser and Z-pinch photo-absorption measurements as well as X-ray emission spectroscopy experiments involving hot dense plasmas produced by ultra-high-intensity laser irradiation. The measured spectra are systematically compared with the fine-structure opacity code SCO-RCG. The focus is on iron, due to its crucial role in understanding asteroseismic observations of β Cephei-type and Slowly Pulsating B stars, as well as of the Sun. For instance, in β Cephei-type stars, the iron-group opacity peak excites acoustic modes through the “kappa-mechanism”. Particular attention is paid to the higher-than-predicted iron opacity measured at the Sandia Z-machine at solar interior conditions. We discuss some theoretical aspects such as density effects, photo-ionization, autoionization or the “filling-the-gap” effect of highly excited states. Full article
(This article belongs to the Special Issue Atomic and Molecular Opacity Data for Astrophysics)
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