When does the onset of multiple stellar populations in star clusters occur? Detection of enriched stellar populations in NGC 2121

Chengyuan Li, Richard de Grijs

    Research output: Contribution to journalArticlepeer-review

    13 Citations (Scopus)
    14 Downloads (Pure)

    Abstract

    Star-to-star light-element abundance variations, known as multiple stellar populations (MPs), are common in almost all Galactic globular clusters. Recently, MPs have also been detected in a number of massive clusters with ages in excess of 2 Gyr in the Large Magellanic Cloud (LMC), thus indicating that age is likely a control parameter for the presence of MPs. However, to conclusively confirm this notion, additional studies of star clusters in the LMC’s “age gap” of 3–6 Gyr are required. Here, we use Hubble Space Telescope observations to study the 3 Gyr old cluster NGC 2121. Compared with so-called “simple” stellar population models, the cluster’s red-giant branch exhibits an apparent spread in a specific color index that is sensitive to intrinsic chemical spreads. The observed spread can be explained by an intrinsic spread in nitrogen abundance of ∼0.5–1.0 dex. NGC 2121 has a comparable mass to its younger counterparts without MPs, indicating that cluster mass might not be the dominant parameter controlling the presence of MPs. The transition phase between the occurrence of clusters with or without MPs seems to occur at ages of 2–3 Gyr, indicating that cluster age may play a dominant role in the establishment of MPs.
    Original languageEnglish
    Article number94
    Pages (from-to)1-8
    Number of pages8
    JournalAstrophysical Journal
    Volume876
    Issue number2
    DOIs
    Publication statusPublished - 8 May 2019

    Bibliographical note

    Copyright 2019 The American Astronomical Society. First published in the Astrophysical Journal, 876(2), 94, 2019, published by IOP Publishing. The original publication is available at http://www.doi.org/10.3847/1538-4357/ab153b. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

    Keywords

    • globular clusters: individual (NGC 2121)
    • Hertzsprung–Russell and C–M diagrams

    Fingerprint

    Dive into the research topics of 'When does the onset of multiple stellar populations in star clusters occur? Detection of enriched stellar populations in NGC 2121'. Together they form a unique fingerprint.

    Cite this