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Frank Grundahl

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

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  • David Yong, Research School of Astronomy and Astrophysics, Australian National University, Canberra
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  • Alan Alves Brito, Research School of Astronomy and Astrophysics, Australian National University, Canberra, Instituto de Física, Universidade Federal do Rio Grande do Sul
  • ,
  • Gary S. Da Costa, Research School of Astronomy and Astrophysics, Australian National University, Canberra
  • ,
  • Javier Alonso-García, Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Santiago, The Milky Way Millennium Nucleus, Santiago
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  • Amanda I. Karakas, Research School of Astronomy and Astrophysics, Australian National University, Canberra
  • ,
  • Marco Pignatari, Department of Physics, University of Basel, Denmark
  • Ian U. Roederer, Department of Astronomy, University of Michigan
  • ,
  • Wako Aoki, National Astronomical Observatory, Mitaka, Tokyo
  • ,
  • Cherie K. Fishlock, Research School of Astronomy and Astrophysics, Australian National University, Canberra
  • ,
  • Frank Grundahl
  • John E. Norris, Research School of Astronomy and Astrophysics, Australian National University, Canberra
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.
Original languageEnglish
JournalRoyal Astronomical Society. Monthly Notices
Volume439
Issue3
Pages (from-to)2638-2650
Number of pages13
ISSN0035-8711
DOIs
Publication statusPublished - 1 Apr 2014

    Research areas

  • stars: abundances, Galaxy: abundances, globular clusters: individual: NGC 6266

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