Metallicities and ages for 35 star clusters and their surrounding fields in the Small Magellanic Cloud

TL;DR

This study uses Strömgren photometry to determine ages and metallicities of 35 star clusters and surrounding fields in the Small Magellanic Cloud, revealing spatial distributions and chemical enrichment patterns.

Contribution

It provides new homogeneous age and metallicity measurements for clusters and fields in the SMC using Strömgren photometry, and constructs the age-metallicity relation for these clusters.

Findings

Younger clusters are centrally concentrated and more metal-rich.

Older clusters are located farther from the SMC center.

The age-metallicity relation aligns with theoretical chemical enrichment models.

Abstract

In this work we study 35 stellar clusters in the Small Magellanic Cloud (SMC) in order to provide their mean metallicities and ages. We also provide mean metallicities of the fields surrounding the clusters. We used Str\"omgren photometry obtained with the 4.1 m SOAR telescope and take advantage of $(b - y)$ and $m1$ colors for which there is a metallicity calibration presented in the literature. The spatial metallicity and age distributions of clusters across the SMC are investigated using the results obtained by Str\"omgren photometry. We confirm earlier observations that younger, more metal-rich star clusters are concentrated in the central regions of the galaxy, while older, more metal-poor clusters are located farther from the SMC center. We construct the age-metallicity relation for the studied clusters and find good agreement with theoretical models of chemical enrichment, and with other literature age and metallicity values for those clusters. We also provide the mean metallicities for old and young populations of the field stars surrounding the clusters, and find the latter to be in good agreement with recent studies of the SMC Cepheid population. Finally, the Str\"omgren photometry obtained for this study is made publicly available.