At the same age, metallicity, and alpha-enhancement, sodium is a more effective tracer of the young and old sequences of the Milky Way disc
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| Format: | Preprint |
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2024
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| _version_ | 1866913543876509696 |
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| author | Owusu, Evans K. Buder, Sven Ruiter, Ashley J. Seitenzahl, Ivo R. Rodríguez-Segovia, Nicolás |
| author_facet | Owusu, Evans K. Buder, Sven Ruiter, Ashley J. Seitenzahl, Ivo R. Rodríguez-Segovia, Nicolás |
| contents | Trends in the enrichment of elements with stellar ages are a powerful avenue to identify unexplained origins of the elements. We investigate the stellar abundance trends of low to intermediate-mass stars using the GALAH DR3 high-resolution spectroscopic dataset of 6234 solar-type stars. Our study explores the elemental abundance [X/Fe] of sodium (Na) with age. We find a pronounced enrichment in [Na/Fe] at super solar metallicity (i.e., [Fe/H] above 0) in the old sequence of Milky Way disc stars, a trend demanding a deeper understanding of the underlying source(s) responsible for the nucleosynthesis. This progressive [Na/Fe] enrichment at the young end of the old sequence has essential implications for Galactic archaeology. In this work, we propose a novel selection technique for separating the Milky Way's thick and thin disc stellar populations (i.e., old and young sequences) based on the observed [Na/Fe] rise of roughly 0.1 dex for stars around 5 - 8 Gyr old. We also compare our selection method to the conventional [Mg/Fe] vs [Fe/H] selection approach, and we find that our new Na-based selection method better disentangles the overlap between young- and old-sequence disc stars at these intermediate ages. This is especially true at super solar [Fe/H], where [Mg/Fe] vs [Fe/H] or [alpha/Fe] vs [Fe/H] separation approaches exhibit a lot of overlap. This new selection method should help us better understand the Milky Way disc's formation history. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2405_00315 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | At the same age, metallicity, and alpha-enhancement, sodium is a more effective tracer of the young and old sequences of the Milky Way disc Owusu, Evans K. Buder, Sven Ruiter, Ashley J. Seitenzahl, Ivo R. Rodríguez-Segovia, Nicolás Astrophysics of Galaxies Solar and Stellar Astrophysics Trends in the enrichment of elements with stellar ages are a powerful avenue to identify unexplained origins of the elements. We investigate the stellar abundance trends of low to intermediate-mass stars using the GALAH DR3 high-resolution spectroscopic dataset of 6234 solar-type stars. Our study explores the elemental abundance [X/Fe] of sodium (Na) with age. We find a pronounced enrichment in [Na/Fe] at super solar metallicity (i.e., [Fe/H] above 0) in the old sequence of Milky Way disc stars, a trend demanding a deeper understanding of the underlying source(s) responsible for the nucleosynthesis. This progressive [Na/Fe] enrichment at the young end of the old sequence has essential implications for Galactic archaeology. In this work, we propose a novel selection technique for separating the Milky Way's thick and thin disc stellar populations (i.e., old and young sequences) based on the observed [Na/Fe] rise of roughly 0.1 dex for stars around 5 - 8 Gyr old. We also compare our selection method to the conventional [Mg/Fe] vs [Fe/H] selection approach, and we find that our new Na-based selection method better disentangles the overlap between young- and old-sequence disc stars at these intermediate ages. This is especially true at super solar [Fe/H], where [Mg/Fe] vs [Fe/H] or [alpha/Fe] vs [Fe/H] separation approaches exhibit a lot of overlap. This new selection method should help us better understand the Milky Way disc's formation history. |
| title | At the same age, metallicity, and alpha-enhancement, sodium is a more effective tracer of the young and old sequences of the Milky Way disc |
| topic | Astrophysics of Galaxies Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2405.00315 |