Detailed Chemical Abundance Analysis of Metal-Poor Turn-Off Stars: One with [Fe/H] < -4 and Three with [Fe/H] < -3
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arXiv
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| Autori principali: | , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866908426587602944 |
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| author | Suda, Takuma Francois, Patrick Wanajo, Shinya Caffau, Elisabetta Aoki, Wako Bonifacio, Piercarlo |
| author_facet | Suda, Takuma Francois, Patrick Wanajo, Shinya Caffau, Elisabetta Aoki, Wako Bonifacio, Piercarlo |
| contents | We present the analysis of four new extremely metal poor turn-off stars thanks to high-resolution spectra obtained with the Subaru/HDS spectrograph. We determined the abundances and upper limits of Li, C, Mg, Ca, Sr, and Ba. Metallicities range from [Fe/H] = -3.3 to -4.4 dex. For one of the stars, we measure the lithium abundance Log(Li/H) = 2.1 {\pm} 0.2. Two stars of the sample have low [α/Fe] abundances. The most metal-poor star of the sample with [Fe/H] = -4.42 dex has a high [Sr/Fe] abundance ratio [Sr/Fe] = 0.9 dex, a high value also found in HE 1327-2326. This star is the second-most iron-poor star observed with Subaru telescope, suggesting that more ultra metal-poor stars could be discovered using high-resolution spectrographs in the Northern Hemisphere. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_18286 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Detailed Chemical Abundance Analysis of Metal-Poor Turn-Off Stars: One with [Fe/H] < -4 and Three with [Fe/H] < -3 Suda, Takuma Francois, Patrick Wanajo, Shinya Caffau, Elisabetta Aoki, Wako Bonifacio, Piercarlo Solar and Stellar Astrophysics Astrophysics of Galaxies We present the analysis of four new extremely metal poor turn-off stars thanks to high-resolution spectra obtained with the Subaru/HDS spectrograph. We determined the abundances and upper limits of Li, C, Mg, Ca, Sr, and Ba. Metallicities range from [Fe/H] = -3.3 to -4.4 dex. For one of the stars, we measure the lithium abundance Log(Li/H) = 2.1 {\pm} 0.2. Two stars of the sample have low [α/Fe] abundances. The most metal-poor star of the sample with [Fe/H] = -4.42 dex has a high [Sr/Fe] abundance ratio [Sr/Fe] = 0.9 dex, a high value also found in HE 1327-2326. This star is the second-most iron-poor star observed with Subaru telescope, suggesting that more ultra metal-poor stars could be discovered using high-resolution spectrographs in the Northern Hemisphere. |
| title | Detailed Chemical Abundance Analysis of Metal-Poor Turn-Off Stars: One with [Fe/H] < -4 and Three with [Fe/H] < -3 |
| topic | Solar and Stellar Astrophysics Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2506.18286 |