Chemical analysis of the Bulge Globular Cluster NGC 6553

TL;DR

This study provides the first detailed chemical abundance analysis of 20 stars in the Bulge Globular Cluster NGC 6553, revealing insights into its chemical patterns and evolutionary history.

Contribution

It presents the first extensive spectroscopic abundance analysis of NGC 6553, measuring multiple elements and analyzing chemical variations among its stars.

Findings

Mean iron content [Fe/H] = -0.10

Detected a significant Na spread

No intrinsic variation in alpha and iron-peak elements

Abstract

Globular Clusters are among the oldest objects in the Galaxy, thus their researchers are key to understanding the processes of evolution and formation that the galaxy has experienced in early stages. Spectroscopic studies allow us to carry out detailed analyzes on the chemical composition of Globular Clusters. The aim of our research is to perform a detailed analysis of chemical abundances to a sample of stars of the Bulge Globular Cluster NGC 6553, in order to determine chemical patterns that allow us to appreciate the phenomenon of Multiple Population in one of the most metal-rich Globular Clusters in the Galaxy. This analysis is being carried out with data obtained by FLAMES/GIRAFFE spectrograph, VVV Survey and DR2 of Gaia Mission. We analyzed 20 Red Horizontal Branch Stars, being the first extensive spectroscopic abundance analysis for this cluster and measured 8 chemical elements (O, Na, Mg, Si, Ca, Ti, Cr and Ni), deriving a mean iron content of $[Fe/H] = -0.10\pm0.01$ and a mean of $[\alpha/Fe] = 0.21\pm0.02$, considering Mg, Si, Ca and Ti (errors on the mean). We found a significant spread in the content of Na but a small or negligible in O. We did not find an intrinsic variation in the content of $\alpha$ and iron-peak elements, showing a good agreement with the trend of the Bulge field stars, suggesting a similar origin and evolution.