Chemical Study of the Metal-rich Globular Cluster NGC 5927

TL;DR

This study provides a detailed chemical abundance analysis of the metal-rich globular cluster NGC 5927, revealing multiple stellar populations and insights into its formation history and Galactic association.

Contribution

It offers the first comprehensive chemical abundance profile of NGC 5927, confirming multiple populations and linking its kinematics to the Galactic Thick Disk.

Findings

Confirmed multiple populations via O-Na anti-correlation.

Determined mean [Fe/H] = -0.47 with minimal spread.

Indicated predominant SNeII contribution from [Ba/Eu] ratios.

Abstract

Globular Clusters (GCs) are natural laboratories where stellar and chemical evolution can be studied in detail. In addition, their chemical patterns and kinematics can tell us wich Galactic structure (Disk, Bulge, Halo or extragalactic) the cluster belongs to. NGC 5927 is one of most metal-rich GCs in the Galaxy and its kinematics links it to the Thick Disk. We present abundance analysis based on high resolution spectra of 7 giant stars. The data were obtained using FLAMES/UVES spectrograph mounted on UT2 telescope of the European Southern Observatory. The principal motivation of this work is to perform a wide and detailed chemical abundance analysis of the cluster and look for possible Multiple Populations (MPs). We determined stellar parameters and measured 22 elements corresponding to light (Na, Al), alpha (O, Mg, Si, Ca, Ti), iron-peak (Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) and heavy elements (Y, Zr, Ba, Ce, Nd, Eu). We found a mean iron content of [Fe/H]=-0.47 $\pm$0.02 (error on the mean). We confirm the existence of MPs in this GC with an O-Na anti-correlation, and moderate spread in Al abundances. We estimate a mean [$\alpha$/Fe]=0.25 $\pm$0.08. Iron-peak elements shows no significant spread. The [Ba/Eu] ratios indicate a predominant contribution from SNeII for the formation of the cluster.