Chemodynamical Analysis of Metal-rich High-eccentricity Stars in the Milky Way's Disk
We present a chemodynamical analysis of 11,562 metal-rich, high-eccentricity halo-like main-sequence stars, which have been referred to as the Splash or Splashed Disk, selected from the Sloan Digital Sky Survey and Large Sky Area Multi-Object Fiber Spectroscopic Telescope. When divided into two grou...
| 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/acb6f5 |
| _version_ | 1797701471794364416 |
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| author | Ayeon Lee Young Sun Lee Young Kwang Kim Timothy C. Beers Deokkeun An |
| author_facet | Ayeon Lee Young Sun Lee Young Kwang Kim Timothy C. Beers Deokkeun An |
| author_sort | Ayeon Lee |
| collection | DOAJ |
| description | We present a chemodynamical analysis of 11,562 metal-rich, high-eccentricity halo-like main-sequence stars, which have been referred to as the Splash or Splashed Disk, selected from the Sloan Digital Sky Survey and Large Sky Area Multi-Object Fiber Spectroscopic Telescope. When divided into two groups, a low-[ α /Fe] population (LAP) and a high-[ α /Fe] population (HAP), based on kinematics and chemistry, we find that they exhibit very distinct properties, indicative of different origins. From a detailed analysis of their orbital inclinations, we suggest that the HAP arises from a large fraction (∼90%) of heated disk stars and a small fraction (∼10%) of in situ stars from a starburst population, likely induced by interaction of the Milky Way with the Gaia-Sausage/Enceladus (GSE) or another early merger. The LAP comprises about half accreted stars from the GSE and half formed by the GSE-induced starburst. Our findings further imply that the Splash stars in our sample originated from at least three different mechanisms: accretion, disk heating, and a merger-induced starburst. |
| first_indexed | 2024-03-12T04:36:12Z |
| format | Article |
| id | doaj.art-8d3e909811634f119462ec17d9a5216b |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T04:36:12Z |
| publishDate | 2023-01-01 |
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| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-8d3e909811634f119462ec17d9a5216b2023-09-03T09:55:22ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194515610.3847/1538-4357/acb6f5Chemodynamical Analysis of Metal-rich High-eccentricity Stars in the Milky Way's DiskAyeon Lee0https://orcid.org/0000-0002-6570-3490Young Sun Lee1https://orcid.org/0000-0001-5297-4518Young Kwang Kim2https://orcid.org/0000-0002-6411-5857Timothy C. Beers3https://orcid.org/0000-0003-4573-6233Deokkeun An4https://orcid.org/0000-0002-8072-7511Department of Astronomy, Space Science, and Geology, Chungnam National University , Daejeon 34134, Republic of KoreaDepartment of Astronomy and Space Science, Chungnam National University , Daejeon 34134, Republic of Korea ; youngsun@cnu.ac.kr; Department of Physics and Astronomy and JINA Center for the Evolution of the Elements, University of Notre Dame , IN 46556, USADepartment of Astronomy and Space Science, Chungnam National University , Daejeon 34134, Republic of Korea ; youngsun@cnu.ac.krDepartment of Physics and Astronomy and JINA Center for the Evolution of the Elements, University of Notre Dame , IN 46556, USADepartment of Science Education, Ewha Womans University , Seoul 03760, Republic of KoreaWe present a chemodynamical analysis of 11,562 metal-rich, high-eccentricity halo-like main-sequence stars, which have been referred to as the Splash or Splashed Disk, selected from the Sloan Digital Sky Survey and Large Sky Area Multi-Object Fiber Spectroscopic Telescope. When divided into two groups, a low-[ α /Fe] population (LAP) and a high-[ α /Fe] population (HAP), based on kinematics and chemistry, we find that they exhibit very distinct properties, indicative of different origins. From a detailed analysis of their orbital inclinations, we suggest that the HAP arises from a large fraction (∼90%) of heated disk stars and a small fraction (∼10%) of in situ stars from a starburst population, likely induced by interaction of the Milky Way with the Gaia-Sausage/Enceladus (GSE) or another early merger. The LAP comprises about half accreted stars from the GSE and half formed by the GSE-induced starburst. Our findings further imply that the Splash stars in our sample originated from at least three different mechanisms: accretion, disk heating, and a merger-induced starburst.https://doi.org/10.3847/1538-4357/acb6f5Milky Way GalaxyMilky Way diskMilky Way dynamicsMilky Way formationMilky Way evolutionStellar abundances |
| spellingShingle | Ayeon Lee Young Sun Lee Young Kwang Kim Timothy C. Beers Deokkeun An Chemodynamical Analysis of Metal-rich High-eccentricity Stars in the Milky Way's Disk The Astrophysical Journal Milky Way Galaxy Milky Way disk Milky Way dynamics Milky Way formation Milky Way evolution Stellar abundances |
| title | Chemodynamical Analysis of Metal-rich High-eccentricity Stars in the Milky Way's Disk |
| title_full | Chemodynamical Analysis of Metal-rich High-eccentricity Stars in the Milky Way's Disk |
| title_fullStr | Chemodynamical Analysis of Metal-rich High-eccentricity Stars in the Milky Way's Disk |
| title_full_unstemmed | Chemodynamical Analysis of Metal-rich High-eccentricity Stars in the Milky Way's Disk |
| title_short | Chemodynamical Analysis of Metal-rich High-eccentricity Stars in the Milky Way's Disk |
| title_sort | chemodynamical analysis of metal rich high eccentricity stars in the milky way s disk |
| topic | Milky Way Galaxy Milky Way disk Milky Way dynamics Milky Way formation Milky Way evolution Stellar abundances |
| url | https://doi.org/10.3847/1538-4357/acb6f5 |
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