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

doi:10.1093/mnras/stx2174

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 language	English
Pages (from-to)	2856-2868
Number of pages	13
Journal	Monthly Notices of the Royal Astronomical Society
Volume	472
Issue number	3
DOIs	https://doi.org/10.1093/mnras/stx2174
Publication status	Published - 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

Access to Document

10.1093/mnras/stx2174

Publisher version (open access)Final published version, 1.88 MBLicence: Unspecified

Cite this

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title = "ESO452-SC11: the lowest mass globular cluster with a potential chemical inhomogeneity",

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.",

keywords = "globular clusters: individual: ESO 452-SC11",

author = "Simpson, {Jeffrey D.} and {De Silva}, Gayandhi and Martell, {Sarah L.} and Navin, {Colin A.} and Zucker, {Daniel B.}",

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.",

year = "2017",

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AU - Simpson, Jeffrey D.

AU - De Silva, Gayandhi

AU - Martell, Sarah L.

AU - Navin, Colin A.

AU - Zucker, Daniel B.

N1 - 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.

PY - 2017/12

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N2 - 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.

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