NLTE Analysis of Y i and Y ii in the Atmospheres of FGK Stars
The nonlocal thermodynamical equilibrium (NLTE) line formation of Y i and Y ii is considered in 1D LTE model atmospheres of FGK-type stars. The model atom was constructed with the most up-to-date atomic data, including quantum cross sections and rate coefficients for transitions in inelastic collisi...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acf5e1 |
| _version_ | 1797654230930030592 |
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| author | Sofya Alexeeva Yu Wang Gang Zhao Feng Wang Yong Wu Jianguo Wang Hongliang Yan Jianrong Shi |
| author_facet | Sofya Alexeeva Yu Wang Gang Zhao Feng Wang Yong Wu Jianguo Wang Hongliang Yan Jianrong Shi |
| author_sort | Sofya Alexeeva |
| collection | DOAJ |
| description | The nonlocal thermodynamical equilibrium (NLTE) line formation of Y i and Y ii is considered in 1D LTE model atmospheres of FGK-type stars. The model atom was constructed with the most up-to-date atomic data, including quantum cross sections and rate coefficients for transitions in inelastic collisions of Y i and Y ii with hydrogen atoms. For seven reference stars, we obtained an agreement between NLTE abundances inferred from the two ionization stages, while the difference in LTE abundance (Y i and Y ii ) can reach up to −0.31 dex. In the atmospheres of FGK-type stars, for both Y i and Y ii lines, the NLTE abundance corrections are positive. In solar metallicity stars, the NLTE abundance corrections for Y ii lines do not exceed 0.12 dex, while in atmospheres of metal-poor stars, they do not exceed 0.21 dex. For Y i lines, the NLTE abundance corrections can reach up to ∼0.5 dex. We determined the yttrium NLTE abundances for a sample of 65 F and G dwarfs and subgiants in the −2.62 ≤ [Fe/H] ≤ +0.24 metallicity range, using high-resolution spectra. For stars with [Fe/H] ≤ −1.5, [Y/Fe] versus [Fe/H] diagram reveals a positive trend with an average value of [Y/Fe] ≃ 0. For metal-poor stars, among Sr, Y, and Zr, the arrangement [Sr/Fe] < [Y/Fe] < [Zr/Fe] remains consistent. The current study is useful for Galactic chemical evolution research. The model atom will be applied for NLTE yttrium abundance determination in very metal-poor stars studied with LAMOST and Subaru. |
| first_indexed | 2024-03-11T16:56:25Z |
| format | Article |
| id | doaj.art-818233b60db044519f351035760e59da |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-11T16:56:25Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-818233b60db044519f351035760e59da2023-10-20T17:18:57ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195711010.3847/1538-4357/acf5e1NLTE Analysis of Y i and Y ii in the Atmospheres of FGK StarsSofya Alexeeva0https://orcid.org/0000-0002-8709-4665Yu Wang1https://orcid.org/0000-0002-2448-3049Gang Zhao2https://orcid.org/0000-0002-8980-945XFeng Wang3https://orcid.org/0000-0002-8514-4497Yong Wu4https://orcid.org/0000-0003-1874-9653Jianguo Wang5Hongliang Yan6https://orcid.org/0000-0002-8609-3599Jianrong Shi7https://orcid.org/0000-0002-0349-7839CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories , Chinese Academy of Sciences, Beijing, 100101, People’s Republic of China ; alexeeva@nao.cas.cnSchool of Physics, Beijing Institute of Technology , Beijing, 100081, People’s Republic of China ; gzhao@nao.cas.cnCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories , Chinese Academy of Sciences, Beijing, 100101, People’s Republic of China ; alexeeva@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of ChinaSchool of Physics, Beijing Institute of Technology , Beijing, 100081, People’s Republic of China ; gzhao@nao.cas.cnInstitute of Applied Physics and Computational Mathematics , Beijing, 100088, People’s Republic of China; HEDPS, Center for Applied Physics and Technology, Peking University , Beijing, 100084, People’s Republic of ChinaInstitute of Applied Physics and Computational Mathematics , Beijing, 100088, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories , Chinese Academy of Sciences, Beijing, 100101, People’s Republic of China ; alexeeva@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 ; alexeeva@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of ChinaThe nonlocal thermodynamical equilibrium (NLTE) line formation of Y i and Y ii is considered in 1D LTE model atmospheres of FGK-type stars. The model atom was constructed with the most up-to-date atomic data, including quantum cross sections and rate coefficients for transitions in inelastic collisions of Y i and Y ii with hydrogen atoms. For seven reference stars, we obtained an agreement between NLTE abundances inferred from the two ionization stages, while the difference in LTE abundance (Y i and Y ii ) can reach up to −0.31 dex. In the atmospheres of FGK-type stars, for both Y i and Y ii lines, the NLTE abundance corrections are positive. In solar metallicity stars, the NLTE abundance corrections for Y ii lines do not exceed 0.12 dex, while in atmospheres of metal-poor stars, they do not exceed 0.21 dex. For Y i lines, the NLTE abundance corrections can reach up to ∼0.5 dex. We determined the yttrium NLTE abundances for a sample of 65 F and G dwarfs and subgiants in the −2.62 ≤ [Fe/H] ≤ +0.24 metallicity range, using high-resolution spectra. For stars with [Fe/H] ≤ −1.5, [Y/Fe] versus [Fe/H] diagram reveals a positive trend with an average value of [Y/Fe] ≃ 0. For metal-poor stars, among Sr, Y, and Zr, the arrangement [Sr/Fe] < [Y/Fe] < [Zr/Fe] remains consistent. The current study is useful for Galactic chemical evolution research. The model atom will be applied for NLTE yttrium abundance determination in very metal-poor stars studied with LAMOST and Subaru.https://doi.org/10.3847/1538-4357/acf5e1Chemical abundancesStellar atmospheresS-processStellar nucleosynthesisGalactic archaeology |
| spellingShingle | Sofya Alexeeva Yu Wang Gang Zhao Feng Wang Yong Wu Jianguo Wang Hongliang Yan Jianrong Shi NLTE Analysis of Y i and Y ii in the Atmospheres of FGK Stars The Astrophysical Journal Chemical abundances Stellar atmospheres S-process Stellar nucleosynthesis Galactic archaeology |
| title | NLTE Analysis of Y i and Y ii in the Atmospheres of FGK Stars |
| title_full | NLTE Analysis of Y i and Y ii in the Atmospheres of FGK Stars |
| title_fullStr | NLTE Analysis of Y i and Y ii in the Atmospheres of FGK Stars |
| title_full_unstemmed | NLTE Analysis of Y i and Y ii in the Atmospheres of FGK Stars |
| title_short | NLTE Analysis of Y i and Y ii in the Atmospheres of FGK Stars |
| title_sort | nlte analysis of y i and y ii in the atmospheres of fgk stars |
| topic | Chemical abundances Stellar atmospheres S-process Stellar nucleosynthesis Galactic archaeology |
| url | https://doi.org/10.3847/1538-4357/acf5e1 |
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