Mon. Not. R. Astron. Soc., 433, 2006-2017 (2013/August-2)
The origin and chemical evolution of the exotic globular cluster NGC 3201.
MUNOZ C., GEISLER D. and VILLANOVA S.
Abstract (from CDS):
NGC 3201 is a globular cluster (GC) which shows very peculiar kinematic characteristics including an extreme radial velocity and a highly retrograde orbit, strongly suggesting an extragalactic origin. Our aims are to study NGC 3201 in the context of multiple populations (MPs), hoping to constrain possible candidates for the self-enrichment by studying the chemical abundance pattern, as well as adding insight into the origin of this intriguing cluster. We present a detailed chemical abundance analysis of eight red giant branch stars using high-resolution spectroscopy. We measured 29 elements and found [Fe/H] = -1.53±0.01; we cannot rule out a metallicity spread of ∼ 0.12dex, and an α-enhancement typical of halo GCs. However, significant spreads are observed in the abundances of all light elements except for Mg. We confirm the presence of an extended Na-O anticorrelation. n-capture elements generally are dominated by the r-process, in good agreement with the bulk of Galactic GCs. The total (C+N+O) abundance is slightly supersolar and requires a small downward correction to the isochrone age, yielding 11.4Gyr. Kinematically, NGC 3201 appears likely to have had an extragalactic origin but its chemical evolution is similar to most other, presumably native, Galactic GCs.