| Issue |
A&A
Volume 614, June 2018
|
|
|---|---|---|
| Article Number | A68 | |
| Number of page(s) | 10 | |
| Section | Galactic structure, stellar clusters and populations | |
| DOI | https://doi.org/10.1051/0004-6361/201732475 | |
| Published online | 15 June 2018 | |
Investigation of a sample of carbon-enhanced metal-poor stars observed with FORS★, and GMOS★★,★★★
1
GEPI, Observatoire de Paris, UniversitL, CNRS,
5 Place Jules Janssen,
92190
Meudon,
France
e-mail: elisabetta.caffau@obspm.fr
2
Max-Planck-Institut für Astronomie,
Königstuhl 17,
69117
Heidelberg,
Germany
3
Departamento de Ciencias Fisicas, Universidad Andres Bello,
Fernandez Concha 700,
Las Condes,
Santiago,
Chile
4
European Southern Observatory,
Casilla
19001,
Santiago,
Chile
Received:
15
December
2017
Accepted:
16
February
2018
Aims. Carbon-enhanced metal-poor (CEMP) stars represent a sizeable fraction of all known metal-poor stars in the Galaxy. Their formation and composition remains a significant topic of investigation within the stellar astrophysics community.
Methods. We analysed a sample of low-resolution spectra of 30 dwarf stars, obtained using the visual and near UV FOcal Reducer and low dispersion Spectrograph for the Very Large Telescope (FORS/VLT) of the European Southern Observatory (ESO) and the Gemini Multi-Object Spectrographs (GMOS) at the GEMINI telescope, to derive their metallicity and carbon abundance.
Results. We derived C and Ca from all spectra, and Fe and Ba from the majority of the stars.
Conclusions. We have extended the population statistics of CEMP stars and have confirmed that in general, stars with a high C abundance belonging to the high C band show a high Ba-content (CEMP-s or -r/s), while stars with a normal C abundance or that are C-rich, but belong to the low C band, are normal in Ba (CEMP-no).
Key words: stars: Population II / stars: abundances / Galaxy: abundances / Galaxy: formation / Galaxy: halo
Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 099.D-0791.
Based on observations obtained at the Gemini Observatory (processed using the Gemini IRAF package), which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), and Ministério da Ciência, Tecnologia e Inovação (Brazil).
Tables 1 and 2 are also available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/614/A68
© ESO 2018
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0;), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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