Barium Abundances of Common Stars in the Gaia-ESO Survey and the LAMOST Medium-resolution Survey
Barium (Ba) abundance has been used as a crucial tracer of both slow and rapid neutron-capture processes to constrain the evolutionary models of the Galaxy. In this study, we aim to establish a reference sample with high-resolution spectra and high-quality stellar parameters from the Gaia-ESO Survey...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/adbbe0 |
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| author | Tian-Yi Chen Jian-Rong Shi Hong-Liang Yan Shuai Liu Chun-Qian Li Xiao-Jin Xie Ze-Ming Zhou Yao-Jia Tang Ming-Yi Ding |
| author_facet | Tian-Yi Chen Jian-Rong Shi Hong-Liang Yan Shuai Liu Chun-Qian Li Xiao-Jin Xie Ze-Ming Zhou Yao-Jia Tang Ming-Yi Ding |
| author_sort | Tian-Yi Chen |
| collection | DOAJ |
| description | Barium (Ba) abundance has been used as a crucial tracer of both slow and rapid neutron-capture processes to constrain the evolutionary models of the Galaxy. In this study, we aim to establish a reference sample with high-resolution spectra and high-quality stellar parameters from the Gaia-ESO Survey (GES). This sample explores the non–local thermodynamic equilibrium (NLTE) effects on the Ba abundances and will support future measurements of Ba abundances for the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) medium-resolution survey (MRS). The sample is composed of 85 common stars of LAMOST MRS DR9 and GES DR5.1, complemented by four metal-poor ([Fe/H] < −1 dex) stars from AMBRE-UVES. The stars cover the ranges of stellar parameters as 4152 K ≤ T _eff ≤ 6866 K, 1.37 $\leqslant \,{\rm{log}}\,g\,\leqslant \,$ 4.57, and −2.40 dex ≤ [Fe/H] ≤ +0.25 dex. We derive the Ba abundances from three Ba ii absorption lines at λλ 5853, 6141, and 6496 Å of R = 47,000 UVES spectra through the spectral synthesis method using the local thermodynamic equilibrium (LTE) and NLTE assumptions. Compared to the GES catalog, the LTE Ba abundances obtained by us from the Ba ii λ 5853 line are the closest to the GES LTE results. The NLTE hypothesis is found to show various impacts on the three lines. The maximum differences from LTE abundances are 0.2, 0.5, and 0.6 dex for the Ba ii lines at λλ 5853, 6141, and 6496 Å, respectively. The NLTE corrections present opposite signs around [Fe/H] = −2.0 dex for the Ba ii line at λ 5853. Stars with higher temperatures or higher Ba abundances suffer larger NLTE effects. A more consistent result of the three lines confirms the necessity of taking NLTE effects into account when determining the Ba abundances. |
| format | Article |
| id | doaj-art-14a5f8aa69dc48f3b95a5d9e18c49abc |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-14a5f8aa69dc48f3b95a5d9e18c49abc2025-08-20T03:44:28ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01982218210.3847/1538-4357/adbbe0Barium Abundances of Common Stars in the Gaia-ESO Survey and the LAMOST Medium-resolution SurveyTian-Yi Chen0https://orcid.org/0000-0002-6448-8995Jian-Rong Shi1https://orcid.org/0000-0002-0349-7839Hong-Liang Yan2https://orcid.org/0000-0002-8609-3599Shuai Liu3https://orcid.org/0000-0001-5193-1727Chun-Qian Li4https://orcid.org/0000-0002-6647-3957Xiao-Jin Xie5https://orcid.org/0000-0002-4440-4803Ze-Ming Zhou6https://orcid.org/0000-0002-1619-1660Yao-Jia Tang7https://orcid.org/0009-0006-3386-4632Ming-Yi Ding8https://orcid.org/0000-0001-6898-7620CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of China; School of Physics and Technology, Nantong University , Nantong 226019, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of China; Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; sjr@nao.cas.cnCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaInstitute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of China; Department of Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaBarium (Ba) abundance has been used as a crucial tracer of both slow and rapid neutron-capture processes to constrain the evolutionary models of the Galaxy. In this study, we aim to establish a reference sample with high-resolution spectra and high-quality stellar parameters from the Gaia-ESO Survey (GES). This sample explores the non–local thermodynamic equilibrium (NLTE) effects on the Ba abundances and will support future measurements of Ba abundances for the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) medium-resolution survey (MRS). The sample is composed of 85 common stars of LAMOST MRS DR9 and GES DR5.1, complemented by four metal-poor ([Fe/H] < −1 dex) stars from AMBRE-UVES. The stars cover the ranges of stellar parameters as 4152 K ≤ T _eff ≤ 6866 K, 1.37 $\leqslant \,{\rm{log}}\,g\,\leqslant \,$ 4.57, and −2.40 dex ≤ [Fe/H] ≤ +0.25 dex. We derive the Ba abundances from three Ba ii absorption lines at λλ 5853, 6141, and 6496 Å of R = 47,000 UVES spectra through the spectral synthesis method using the local thermodynamic equilibrium (LTE) and NLTE assumptions. Compared to the GES catalog, the LTE Ba abundances obtained by us from the Ba ii λ 5853 line are the closest to the GES LTE results. The NLTE hypothesis is found to show various impacts on the three lines. The maximum differences from LTE abundances are 0.2, 0.5, and 0.6 dex for the Ba ii lines at λλ 5853, 6141, and 6496 Å, respectively. The NLTE corrections present opposite signs around [Fe/H] = −2.0 dex for the Ba ii line at λ 5853. Stars with higher temperatures or higher Ba abundances suffer larger NLTE effects. A more consistent result of the three lines confirms the necessity of taking NLTE effects into account when determining the Ba abundances.https://doi.org/10.3847/1538-4357/adbbe0Stellar abundances |
| spellingShingle | Tian-Yi Chen Jian-Rong Shi Hong-Liang Yan Shuai Liu Chun-Qian Li Xiao-Jin Xie Ze-Ming Zhou Yao-Jia Tang Ming-Yi Ding Barium Abundances of Common Stars in the Gaia-ESO Survey and the LAMOST Medium-resolution Survey The Astrophysical Journal Stellar abundances |
| title | Barium Abundances of Common Stars in the Gaia-ESO Survey and the LAMOST Medium-resolution Survey |
| title_full | Barium Abundances of Common Stars in the Gaia-ESO Survey and the LAMOST Medium-resolution Survey |
| title_fullStr | Barium Abundances of Common Stars in the Gaia-ESO Survey and the LAMOST Medium-resolution Survey |
| title_full_unstemmed | Barium Abundances of Common Stars in the Gaia-ESO Survey and the LAMOST Medium-resolution Survey |
| title_short | Barium Abundances of Common Stars in the Gaia-ESO Survey and the LAMOST Medium-resolution Survey |
| title_sort | barium abundances of common stars in the gaia eso survey and the lamost medium resolution survey |
| topic | Stellar abundances |
| url | https://doi.org/10.3847/1538-4357/adbbe0 |
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