Abundance analysis of three new extremely metal-poor stars, including one CEMP-s star
Abstract
We report a detailed abundance analysis of three extremely metal-poor (EMP) stars thanks to spectra obtained with the high-dispersion spectrograph (HDS) at the Subaru telescope. The aim is to observe a sample of EMP candidate stars selected from the Sloan Digital Sky Survey (SDSS) and determine their detailed chemical composition. High-resolution spectra of three faint turn-off stars using HDS on the Subaru telescope were acquired.We used standard 1D models to compute the abundances of several elements (Li, C, Mg, Ca, Sr, and Ba). The stars we analysed have a metallicity [Fe/H] of between -3.02 and -3.57 dex. We also measured accurate radial velocities that, coupled with the Gaia astrometric data, allowed us to compute actions and Galactic orbits for the stars. Our analysis confirms that the stars are genuine EMP stars. One of them (SDSS J074238.68 +470537.0) can be classified as a CEMP-s star with the highest [Mg/Fe] ratio ever measured in a turn-off CEMP-s star with [Mg/Fe] = 1.85 dex. For the star SDSS J012630.30+073029.3 ([Fe/H]= -3.02 dex), we have a clear detection of lithium with A(Li) = 2.05. Kinematically, SDSS J214340.08-002835.5 is a thick-disc star, while the other two belong to the halo and are candidate members of the Gaia- Sausage-Enceladus.
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BibTeX
@misc{francois2026abundance,
title = {{Abundance analysis of three new extremely metal-poor stars, including one CEMP-s star}},
author = {P. François and T. Suda and S. Wanajo and E. Caffau and P. Bonifacio and W. Aoki and S. Yamada and M. Y. Fujimoto},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.37613},
eprint = {2609.37613},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.37613},
}
RIS
TY - UNPB
TI - Abundance analysis of three new extremely metal-poor stars, including one CEMP-s star
AU - P. François
AU - T. Suda
AU - S. Wanajo
AU - E. Caffau
AU - P. Bonifacio
AU - W. Aoki
AU - S. Yamada
AU - M. Y. Fujimoto
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.37613
UR - https://arxiv.org/abs/2609.37613
AB - We report a detailed abundance analysis of three extremely metal-poor (EMP) stars thanks to spectra obtained with the high-dispersion spectrograph (HDS) at the Subaru telescope. The aim is to observe a sample of EMP candidate stars selected from the Sloan Digital Sky Survey (SDSS) and determine their detailed chemical composition. High-resolution spectra of three faint turn-off stars using HDS on the Subaru telescope were acquired.We used standard 1D models to compute the abundances of several elements (Li, C, Mg, Ca, Sr, and Ba). The stars we analysed have a metallicity [Fe/H] of between -3.02 and -3.57 dex. We also measured accurate radial velocities that, coupled with the Gaia astrometric data, allowed us to compute actions and Galactic orbits for the stars. Our analysis confirms that the stars are genuine EMP stars. One of them (SDSS J074238.68 +470537.0) can be classified as a CEMP-s star with the highest [Mg/Fe] ratio ever measured in a turn-off CEMP-s star with [Mg/Fe] = 1.85 dex. For the star SDSS J012630.30+073029.3 ([Fe/H]= -3.02 dex), we have a clear detection of lithium with A(Li) = 2.05. Kinematically, SDSS J214340.08-002835.5 is a thick-disc star, while the other two belong to the halo and are candidate members of the Gaia- Sausage-Enceladus.
ER -