EXTENDED STAR FORMATION IN THE INTERMEDIATE-AGE LARGE MAGELLANIC CLOUD STAR CLUSTER NGC 2209

Journal Article · Mon Dec 10 04:00:00 EST 2012 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/761/1/L5· OSTI ID:22078397

Keller, Stefan C; Mackey, A Dougal; Da Costa, Gary S ^[1]

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1. Research School of Astronomy and Astrophysics, Australian National University, Canberra (Australia)

We present observations of the 1 Gyr old star cluster NGC 2209 in the Large Magellanic Cloud made with the GMOS imager on the Gemini South Telescope. These observations show that the cluster exhibits a main-sequence turnoff that spans a broader range in luminosity than can be explained by a single-aged stellar population. This places NGC 2209 amongst a growing list of intermediate-age (1-3 Gyr) clusters that show evidence for extended or multiple epochs of star formation of between 50 and 460 Myr in extent. The extended main-sequence turnoff observed in NGC 2209 is a confirmation of the prediction in Keller et al. made on the basis of the cluster's large core radius. We propose that secondary star formation is a defining feature of the evolution of massive star clusters. Dissolution of lower mass clusters through evaporation results in only clusters that have experienced secondary star formation surviving for a Hubble time, thus providing a natural connection between the extended main-sequence turnoff phenomenon and the ubiquitous light-element abundance ranges seen in the ancient Galactic globular clusters.

• OSTI ID: 22078397
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 761; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
DISSOLUTION
ELEMENT ABUNDANCE
EVAPORATION
LUMINOSITY
MAGELLANIC CLOUDS
MASS
STAR CLUSTERS
STAR EVOLUTION
TELESCOPES