Evidence for multiple populations in the intermediate-age cluster Lindsay 1 in the SMC

Lindsay 1 is an intermediate-age (≈8 Gyr) massive cluster in the Small Magellanic Cloud. Using VLT FORS2 spectra of 16 probable cluster members on the lower red giant branch of the cluster, we measure CN and CH band strengths (at ≃ 3883 and 4300 Å, respectively), along with carbon and nitrogen abun...

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Main Authors: Hollyhead, Katie (Author) , Kacharov, Nikolay (Author) , Lardo, C. (Author) , Bastian, Nate (Author) , Hilker, Michael (Author) , Koch-Hansen, Andreas (Author) , Grebel, Eva K. (Author)
Format: Article (Journal)
Language:English
Published: 2017
In: Monthly notices of the Royal Astronomical Society. Letters
Year: 2017, Volume: 465, Issue: 1, Pages: L39-L43
ISSN:1745-3933
DOI:10.1093/mnrasl/slw179
Online Access:Verlag, Volltext: http://dx.doi.org/10.1093/mnrasl/slw179
Verlag, Volltext: https://academic.oup.com/mnrasl/article/465/1/L39/2435127/Evidence-for-multiple-populations-in-the
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Author Notes:K. Hollyhead, N. Kacharov, C. Lardo, N. Bastian, M. Hilker, M. Rejkuba, A. Koch, E.K. Grebel, I. Georgiev
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Summary:Lindsay 1 is an intermediate-age (≈8 Gyr) massive cluster in the Small Magellanic Cloud. Using VLT FORS2 spectra of 16 probable cluster members on the lower red giant branch of the cluster, we measure CN and CH band strengths (at ≃ 3883 and 4300 Å, respectively), along with carbon and nitrogen abundances and find that a sub-population of stars has significant nitrogen enrichment. A lack of spread in carbon abundances excludes evolutionary mixing as the source of this enrichment, so we conclude that this is evidence of multiple populations. Therefore, Lindsay 1 is the youngest cluster to show such variations, implying that the process triggering the onset of multiple populations must operate until at least redshift ∼1.
Item Description:Published: 12 September 2016
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Physical Description:Online Resource
ISSN:1745-3933
DOI:10.1093/mnrasl/slw179