THE EXTENDED MAIN-SEQUENCE TURNOFF CLUSTERS OF THE LARGE MAGELLANIC CLOUD-MISSING LINKS IN GLOBULAR CLUSTER EVOLUTION

Journal Article · Sun Apr 10 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/731/1/22· OSTI ID:21574779

Keller, Stefan C; Mackey, A Dougal

Recent observations of intermediate-age (1-3 Gyr) massive star clusters in the Large Magellanic Cloud have revealed that the majority possess bifurcated or extended main-sequence turnoff (EMSTO) morphologies. This effect can be understood to arise from subsequent star formation among the stellar population with age differences between constituent stars amounting to 50-300 Myr. Age spreads of this order are similarly invoked to explain the light-element abundance variations witnessed in ancient globular clusters (GCs). In this paper, we explore the proposition that the clusters exhibiting the EMSTO phenomenon are a general phase in the evolution of massive clusters, one that naturally leads to the particular chemical properties of the ancient GC population. We show that the isolation of EMSTO clusters to intermediate ages is the consequence of observational selection effects. In our proposed scenario, the EMSTO phenomenon is identical to that which establishes the light-element abundance variations that are ubiquitous in the ancient GC population. Our scenario makes a strong prediction: EMSTO clusters will exhibit abundance variations in the light-elements characteristic of the ancient GC population.

• OSTI ID: 21574779
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 731; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
ELEMENT ABUNDANCE
EVOLUTION
GALAXIES
MAGELLANIC CLOUDS
STAR CLUSTERS
VARIATIONS