Detailed Opacity Calculations for Astrophysical Applications
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 e...
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MDPI AG
2017-05-01
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| Շարք: | Atoms |
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| Առցանց հասանելիություն: | http://www.mdpi.com/2218-2004/5/2/22 |
| _version_ | 1828497787970387968 |
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| author | Jean-Christophe Pain Franck Gilleron Maxime Comet |
| author_facet | Jean-Christophe Pain Franck Gilleron Maxime Comet |
| author_sort | Jean-Christophe Pain |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-12-11T12:53:55Z |
| format | Article |
| id | doaj.art-bc34c0300b8c4776b3b8f62f4528e04b |
| institution | Directory Open Access Journal |
| issn | 2218-2004 |
| language | English |
| last_indexed | 2024-12-11T12:53:55Z |
| publishDate | 2017-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Atoms |
| spelling | doaj.art-bc34c0300b8c4776b3b8f62f4528e04b2022-12-22T01:06:37ZengMDPI AGAtoms2218-20042017-05-01522210.3390/atoms5020022atoms5020022Detailed Opacity Calculations for Astrophysical ApplicationsJean-Christophe Pain0Franck Gilleron1Maxime Comet2CEA, DAM, DIF, F-91297 Arpajon, FranceCEA, DAM, DIF, F-91297 Arpajon, FranceCEA, DAM, DIF, F-91297 Arpajon, FranceNowadays, 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.http://www.mdpi.com/2218-2004/5/2/22atomic physicsspectroscopyastrophysicsβ Cepheiwhite dwarfsstellar envelopesradiative zone of the Sun |
| spellingShingle | Jean-Christophe Pain Franck Gilleron Maxime Comet Detailed Opacity Calculations for Astrophysical Applications Atoms atomic physics spectroscopy astrophysics β Cephei white dwarfs stellar envelopes radiative zone of the Sun |
| title | Detailed Opacity Calculations for Astrophysical Applications |
| title_full | Detailed Opacity Calculations for Astrophysical Applications |
| title_fullStr | Detailed Opacity Calculations for Astrophysical Applications |
| title_full_unstemmed | Detailed Opacity Calculations for Astrophysical Applications |
| title_short | Detailed Opacity Calculations for Astrophysical Applications |
| title_sort | detailed opacity calculations for astrophysical applications |
| topic | atomic physics spectroscopy astrophysics β Cephei white dwarfs stellar envelopes radiative zone of the Sun |
| url | http://www.mdpi.com/2218-2004/5/2/22 |
| work_keys_str_mv | AT jeanchristophepain detailedopacitycalculationsforastrophysicalapplications AT franckgilleron detailedopacitycalculationsforastrophysicalapplications AT maximecomet detailedopacitycalculationsforastrophysicalapplications |