Searching for R-process-enhanced Stars in the LAMOST Survey. II. Two New r-II Stars in the Milky Way Disk
R -process-enhanced (RPE) stars are rare and typically metal-poor ([Fe/H] < −1.0), primarily found in the Milky Way halo system and dwarf galaxies. This study reports the discovery of two relatively bright, highly RPE stars ([Eu/Fe] > +0.70) located in the Milky Way disk, with [Fe/H] of −0....
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adc807 |
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| author | Xiao-Jin Xie Jianrong Shi Hong-Liang Yan Tian-Yi Chen Carlos Allende Prieto Timothy C. Beers Shi-Lun Jin Shuai Liu Chun-Qian Li Ze-Ming Zhou Ming-Yi Ding Yao-Jia Tang |
| author_facet | Xiao-Jin Xie Jianrong Shi Hong-Liang Yan Tian-Yi Chen Carlos Allende Prieto Timothy C. Beers Shi-Lun Jin Shuai Liu Chun-Qian Li Ze-Ming Zhou Ming-Yi Ding Yao-Jia Tang |
| author_sort | Xiao-Jin Xie |
| collection | DOAJ |
| description | R -process-enhanced (RPE) stars are rare and typically metal-poor ([Fe/H] < −1.0), primarily found in the Milky Way halo system and dwarf galaxies. This study reports the discovery of two relatively bright, highly RPE stars ([Eu/Fe] > +0.70) located in the Milky Way disk, with [Fe/H] of −0.34 and −0.80, respectively. These two stars are selected from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope medium-resolution ( R ∼ 7500) spectroscopic survey. Follow-up high-resolution ( R ∼ 25,000) observations were conducted with the High Optical Resolution Spectrograph installed on the 10.4 m Gran Telescopio Canarias. We perform the determination of elemental abundances and calculate the orbital parameters. We find that they are r -II stars with elemental abundances in agreement with the solar r -process pattern. These two objects are chemically and dynamically consistent with membership in the Galactic disk and exhibit no evidence of being part of accreted systems. |
| format | Article |
| id | doaj-art-2fe2be97f3cf427999c9729a0718e89e |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-2fe2be97f3cf427999c9729a0718e89e2025-08-20T03:48:52ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01984217610.3847/1538-4357/adc807Searching for R-process-enhanced Stars in the LAMOST Survey. II. Two New r-II Stars in the Milky Way DiskXiao-Jin Xie0https://orcid.org/0000-0002-4440-4803Jianrong Shi1https://orcid.org/0000-0002-0349-7839Hong-Liang Yan2https://orcid.org/0000-0002-8609-3599Tian-Yi Chen3https://orcid.org/0000-0002-6448-8995Carlos Allende Prieto4https://orcid.org/0000-0002-0084-572XTimothy C. Beers5https://orcid.org/0000-0003-4573-6233Shi-Lun Jin6https://orcid.org/0000-0002-2868-8658Shuai Liu7https://orcid.org/0000-0001-5193-1727Chun-Qian Li8https://orcid.org/0000-0002-6647-3957Ze-Ming Zhou9https://orcid.org/0000-0002-1619-1660Ming-Yi Ding10https://orcid.org/0000-0001-6898-7620Yao-Jia Tang11https://orcid.org/0009-0006-3386-4632CAS Key Laboratory of Optical Astronomy , National Astronomical Observatories, Chinese Academy of Science, Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn, hlyan@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 Science, Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn, hlyan@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 Science, Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn, hlyan@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 China ; zzm@bnu.edu.cnCAS Key Laboratory of Optical Astronomy , National Astronomical Observatories, Chinese Academy of Science, Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn, hlyan@nao.cas.cn; School of Astronomy and Space Science , University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of ChinaInstituto de Astrofísica de Canarias , Vía Láctea S/N, E-38205 La Laguna, Tenerife, Spain; Universidad de La Laguna , Departamento de Astrofísica, E-38206 La Laguna, Tenerife, SpainDepartment of Physics and Astronomy and JINA Center for the Evolution of the Elements (JINA-CEE) , University of Notre Dame, Notre Dame, IN 46556, USAInstitute of Modern Physics , Chinese Academy of Science, Lanzhou 730000, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy , National Astronomical Observatories, Chinese Academy of Science, Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn, hlyan@nao.cas.cnSchool 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 China ; zzm@bnu.edu.cnInstitute for Frontiers in Astronomy and Astrophysics , Beijing Normal University, Beijing 102206, People’s Republic of China ; zzm@bnu.edu.cn; School of Physics and Astronomy , Beijing Normal University, Beijing 100875, People’s Republic of ChinaNanjing Institute of Astronomical and Optics & Technology , Chinese Academy of Sciences, Nanjing 210042, People’s Republic of China; CAS Key Laboratory of Astronomical Optics & Technology , Nanjing Institute of Astronomical Optics & Technology, Nanjing 210042, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy , National Astronomical Observatories, Chinese Academy of Science, Beijing 100101, People’s Republic of China ; sjr@nao.cas.cn, hlyan@nao.cas.cn; School of Astronomy and Space Science , University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of ChinaR -process-enhanced (RPE) stars are rare and typically metal-poor ([Fe/H] < −1.0), primarily found in the Milky Way halo system and dwarf galaxies. This study reports the discovery of two relatively bright, highly RPE stars ([Eu/Fe] > +0.70) located in the Milky Way disk, with [Fe/H] of −0.34 and −0.80, respectively. These two stars are selected from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope medium-resolution ( R ∼ 7500) spectroscopic survey. Follow-up high-resolution ( R ∼ 25,000) observations were conducted with the High Optical Resolution Spectrograph installed on the 10.4 m Gran Telescopio Canarias. We perform the determination of elemental abundances and calculate the orbital parameters. We find that they are r -II stars with elemental abundances in agreement with the solar r -process pattern. These two objects are chemically and dynamically consistent with membership in the Galactic disk and exhibit no evidence of being part of accreted systems.https://doi.org/10.3847/1538-4357/adc807R-processNucleosynthesisStellar abundancesMilky Way disk |
| spellingShingle | Xiao-Jin Xie Jianrong Shi Hong-Liang Yan Tian-Yi Chen Carlos Allende Prieto Timothy C. Beers Shi-Lun Jin Shuai Liu Chun-Qian Li Ze-Ming Zhou Ming-Yi Ding Yao-Jia Tang Searching for R-process-enhanced Stars in the LAMOST Survey. II. Two New r-II Stars in the Milky Way Disk The Astrophysical Journal R-process Nucleosynthesis Stellar abundances Milky Way disk |
| title | Searching for R-process-enhanced Stars in the LAMOST Survey. II. Two New r-II Stars in the Milky Way Disk |
| title_full | Searching for R-process-enhanced Stars in the LAMOST Survey. II. Two New r-II Stars in the Milky Way Disk |
| title_fullStr | Searching for R-process-enhanced Stars in the LAMOST Survey. II. Two New r-II Stars in the Milky Way Disk |
| title_full_unstemmed | Searching for R-process-enhanced Stars in the LAMOST Survey. II. Two New r-II Stars in the Milky Way Disk |
| title_short | Searching for R-process-enhanced Stars in the LAMOST Survey. II. Two New r-II Stars in the Milky Way Disk |
| title_sort | searching for r process enhanced stars in the lamost survey ii two new r ii stars in the milky way disk |
| topic | R-process Nucleosynthesis Stellar abundances Milky Way disk |
| url | https://doi.org/10.3847/1538-4357/adc807 |
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