Investigation of a sample of carbon-enhanced metal-poor stars observed with FORS and GMOS

TL;DR

This study analyzed low-resolution spectra of 30 metal-poor dwarf stars to investigate their carbon and metal abundances, expanding understanding of the characteristics and classifications of carbon-enhanced metal-poor stars in the Galaxy.

Contribution

It provides new population statistics of CEMP stars and confirms correlations between carbon and barium abundances in different CEMP subclasses.

Findings

High C band stars tend to have high Ba content (CEMP-s or -r/s).

Low C band stars generally show normal Ba levels (CEMP-no).

Extended the statistical understanding of CEMP star populations.

Abstract

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. We analysed a sample of low-resolution spectra of 30 dwarf stars, obtained using the 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. We derived C and Ca from all spectra, and Fe and Ba from the majority of the stars. 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).