Detailed Chemical Abundances of Star Clusters in the Large Magellanic Cloud

TL;DR

This study presents the first detailed chemical abundance measurements of three Large Magellanic Cloud star clusters using integrated-light spectroscopy, revealing insights into their chemical compositions and potential multiple stellar populations.

Contribution

It provides the first detailed chemical abundances for three LMC clusters from integrated-light spectra, comparing results with existing models and literature.

Findings

[Fe/H] and element ratios match literature and models

Possible Mg-Al anti-correlation in some clusters

Enhanced [Na/Fe] suggests intracluster variations

Abstract

We derive the first detailed chemical abundances of three star clusters in the Large Magellanic Cloud (LMC), NGC1831 (436+/-22 Myr), NGC1856 (350+/-18 Myr) and [SL63]268 (1230+/-62 Myr) using integrated-light spectroscopic observations obtained with the Magellan Echelle spectrograph on Magellan Baade telescope. We derive [Fe/H], [Mg/Fe], [Ti/Fe], [Ca/Fe], [Ni/Fe], [Mn/Fe], [Cr/Fe] and [Na/Fe] for the three clusters. Overall, our results match the LMC abundances obtained in the literature as well as those predicted by detailed chemical evolution models. For clusters NGC1831 and NGC1856, the [Mg/Fe] ratios appear to be slightly depleted compared to [Ca/Fe] and [Ti/Fe]. This could be hinting at the well-known Mg-Al abundance anti-correlation observed in several Milky Way globular clusters. We note, however, that higher signal-to-noise observations are needed to confirm such a scenario, particularly for NGC 1831. We also find a slightly enhanced integrated-light [Na/Fe] ratio for cluster [SL63]268 compared to those from the LMC field stars, possibly supporting a scenario of intracluster abundance variations. We stress that detailed abundance analysis of individual stars in these LMC clusters is required to confirm the presence or absence of MSPs.