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Chemical abundances in bright giants of the globular cluster M62 (NGC 6266)

Alonso-Garcia, Javier; Brito, Alan; Yong, David; Alves Brito, Alan; Da Costa, Gary S.; Alonso-García, Javier; Karakas, Amanda I.; Pignatari, Marco; Roederer, Ian U.; Aoki, Wako; Fishlock, Cherie K.; Grundahl, Frank; Norris, John E.

Authors

Javier Alonso-Garcia

Alan Brito

David Yong

Alan Alves Brito

Gary S. Da Costa

Javier Alonso-García

Amanda I. Karakas

Ian U. Roederer

Wako Aoki

Cherie K. Fishlock

Frank Grundahl

John E. Norris

Abstract

With the exception of Terzan 5, all the Galactic globular clusters that possess significant metallicity spreads, such as ω Cen and M22, are preferentially the more luminous clusters with extended horizontal branches. Here we present radial velocities and chemical abundances for seven bright giants in the globular cluster M62, a previously little-studied cluster. With MV = −9.18, M62 is the ninth most luminous Galactic globular cluster and has an extended horizontal branch. Within our sample, we find (i) no evidence for a dispersion in metallicity, [Fe/H], beyond the measurement uncertainties, (ii) star-to-star abundance variations for C, O, Na and Al with the usual correlations between these elements as seen in other globular clusters, and (iii) a global enrichment for the elements Zr, Ba and La at the level [X/Fe] ≃ +0.4 dex. For elements heavier than La, the abundance ratios are consistent with the scaled-solar r-process distribution. Below La, the abundances are anomalous when compared to the scaled-solar s-process or r-process distributions. For these elements, the abundance signature in M62 is in agreement with predictions of the s-process from fast-rotating massive stars, although the high [Rb/Y] ratio we measure may be a challenge to this scenario.

Journal Article Type Article
Publication Date Apr 11, 2014
Journal Monthly notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Oxford University Press (OUP)
Peer Reviewed Peer Reviewed
Volume 439
Issue 3
Pages 2638-2650
Institution Citation Yong, D., Alves Brito, A., Da Costa, G. S., Alonso-García, J., Karakas, A. I., Pignatari, M., …Norris, J. E. (2014). Chemical abundances in bright giants of the globular cluster M62 (NGC 6266). Monthly notices, containing papers, abstracts of papers, and reports of the proceedings of the Society, 439(3), 2638-2650. https://doi.org/10.1093/mnras/stu118
DOI https://doi.org/10.1093/mnras/stu118
Keywords Stars : abundances, Galaxy : abundances, Globular clusters : individual : NGC 6266
Publisher URL http://mnras.oxfordjournals.org/content/439/3/2638.full#fn-12
Additional Information This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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