CAPOS: the bulge Cluster APOgee Survey IV elemental abundances of the bulge globular cluster NGC 6558
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Archivos
Fecha
2023-12-01
Profesor/a Guía
Facultad/escuela
Idioma
en
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Editor
Oxford University Press
Nombre de Curso
Licencia CC
CC BY 4.0 DEED
Attribution 4.0 International
Licencia CC
https://creativecommons.org/licenses/by/4.0/
Resumen
This study presents the results concerning six red giant stars members of the globular cluster NGC 6558. Our analysis utilized high-resolution near-infrared spectra obtained through the CAPOS initiative (the APOgee Survey of Clusters in the Galactic Bulge), which focuses on surveying clusters within the Galactic Bulge, as a component of the Apache Point Observatory Galactic Evolution Experiment II survey (APOGEE-2). We employ the Brussels Automatic Code for Characterizing High accUracy Spectra (BACCHUS) code to provide line-by-line elemental-abundances for Fe-peak (Fe, Ni), α-(O, Mg, Si, Ca, Ti), light-(C, N), odd-Z (Al), and the s-process element (Ce) for the four stars with high-signal-to-noise ratios. This is the first reliable measure of the CNO abundances for NGC 6558. Our analysis yields a mean metallicity for NGC 6558 of 〈[Fe/H]〉 = −1.15 ± 0.08, with no evidence for a metallicity spread. We find a Solar Ni abundance, 〈[Ni/Fe]〉 ∼ +0.01, and a moderate enhancement of α-elements, ranging between +0.16 and [removed] +0.99, along with a low level of carbon, [C/Fe] < −0.12. This behaviour of Nitrogen-Carbon is a typical chemical signature for the presence of multiple stellar populations in virtually all GCs; this is the first time that it is reported in NGC 6558. We also observed a remarkable consistency in the behaviour of all the chemical species compared to the other CAPOS bulge GCs of the same metallicity. © The Author(s) 2023.
Notas
INDEXACIÓN: SCOPUS.
Palabras clave
galaxy: globular clusters: individual: NGC 6558, stars: abundances, stars: chemically peculiar, Techniques: spectroscopic
Citación
Monthly Notices of the Royal Astronomical Society, Volume 526, Issue 4, Pages 6274 - 6283, 1 December 2023
DOI
10.1093/mnras/stad3178