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| Main Authors: | , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2510.15654 |
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| _version_ | 1866909852761063424 |
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| author | Lu, Yuxi Manea, Catherine Sayeed, Maryum Douglas, Stephanie T. McKenzie, Madeleine Rowan, Dominick Ilyin, Ilya Wheeler, Adam Buder, Sven Amard, Louis Pinsonneault, Marc H. Johnson, Jennifer A. |
| author_facet | Lu, Yuxi Manea, Catherine Sayeed, Maryum Douglas, Stephanie T. McKenzie, Madeleine Rowan, Dominick Ilyin, Ilya Wheeler, Adam Buder, Sven Amard, Louis Pinsonneault, Marc H. Johnson, Jennifer A. |
| contents | The question of whether genuinely young high-$α$ stars exist has been discussed for over a decade since their discovery from asteroseismology of giant stars as it is challenging to break the degeneracy between the binary interaction and the genuinely young scenarios. Young high-$α$ stars are hard to explain with traditional chemical evolution model as the high-$α$ disk is typically associated with the early epoch of star formation in the Milky Way. Combined with recent advances of gyrochronology, and that $^7$Li can serve as an unambiguous indicator for identifying merger products in dwarfs thanks to its low burning temperature, we identified young high-$α$ dwarf candidate stars through their fast rotation in a previous study. In this paper, we performed high-resolution spectroscopic follow-up of these candidates using Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI), and confirm 3 additional stars that are most likely genuinely young. Together with the star from the earlier paper, we find three out of four of them center around [Fe/H]=-0.5 dex, are ~5 Gyr old, and have a similar amount of elevated Li (~0.5 dex) and Al (~0.1 dex) compared to stars with matching $\log g$, $T_{\rm eff}$, Mg, and Fe within observational uncertainties, hinting at their common formation pathway. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_15654 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Spectroscopic Follow-up of Young High-$α$ Dwarf Star Candidates: Still Likely Genuinely Young Lu, Yuxi Manea, Catherine Sayeed, Maryum Douglas, Stephanie T. McKenzie, Madeleine Rowan, Dominick Ilyin, Ilya Wheeler, Adam Buder, Sven Amard, Louis Pinsonneault, Marc H. Johnson, Jennifer A. Astrophysics of Galaxies Solar and Stellar Astrophysics The question of whether genuinely young high-$α$ stars exist has been discussed for over a decade since their discovery from asteroseismology of giant stars as it is challenging to break the degeneracy between the binary interaction and the genuinely young scenarios. Young high-$α$ stars are hard to explain with traditional chemical evolution model as the high-$α$ disk is typically associated with the early epoch of star formation in the Milky Way. Combined with recent advances of gyrochronology, and that $^7$Li can serve as an unambiguous indicator for identifying merger products in dwarfs thanks to its low burning temperature, we identified young high-$α$ dwarf candidate stars through their fast rotation in a previous study. In this paper, we performed high-resolution spectroscopic follow-up of these candidates using Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI), and confirm 3 additional stars that are most likely genuinely young. Together with the star from the earlier paper, we find three out of four of them center around [Fe/H]=-0.5 dex, are ~5 Gyr old, and have a similar amount of elevated Li (~0.5 dex) and Al (~0.1 dex) compared to stars with matching $\log g$, $T_{\rm eff}$, Mg, and Fe within observational uncertainties, hinting at their common formation pathway. |
| title | Spectroscopic Follow-up of Young High-$α$ Dwarf Star Candidates: Still Likely Genuinely Young |
| topic | Astrophysics of Galaxies Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2510.15654 |