ESO452-SC11

the lowest mass globular cluster with a potential chemical inhomogeneity

Jeffrey D. Simpson*, Gayandhi De Silva, Sarah L. Martell, Colin A. Navin, Daniel B. Zucker

*Corresponding author for this work

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Abstract

We present the largest spectroscopic investigation of one of the faintest and least studied stellar clusters of the MilkyWay, ESO 452-SC11. Using the Anglo-Australian Telescope AAOmega and Keck High Resolution Echelle Spectrometer spectrographs we have identified 11 members of the cluster and found indications of star-to-star light element abundance variation, primarily using the blue cyanogen absorption features. From a stellar density profile, we estimate a total cluster mass of (6.8 +/- 3.4) x 10³M⊙. This would make ESO 452-SC11 the lowest mass cluster with evidence for multiple populations. These data were also used to measure the radial velocity of the cluster (16.7 +/- 0.3 kms¯¹) and confirm that ESO 452-SC11 is relatively metal rich for a globular cluster ([Fe/H]= -0.81 +/- 0.13). All known massive clusters studied in detail show multiple populations of stars each with a different chemical composition, but many low-mass globular clusters appear to be chemically homogeneous. ESO 452-SC11 sets a lower mass limit for the multiple stellar population phenomenon.

Original languageEnglish
Pages (from-to)2856-2868
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume472
Issue number3
DOIs
Publication statusPublished - Dec 2017

Bibliographical note

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society, 472(3), pp.2856–2868. The original publication is available at https://doi.org/10.1093/mnras/stx2174. Copyright 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Keywords

  • globular clusters: individual: ESO 452-SC11

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