Globular clusters: a chemical roadmap between anomalies and homogeneity

TL;DR

Recent studies show that globular clusters, once thought to be chemically uniform, actually exhibit complex chemical variations, especially in light elements, challenging previous assumptions of their simplicity.

Contribution

This paper reviews recent spectroscopic and photometric evidence revealing chemical anomalies and heterogeneity in globular clusters, updating the traditional view of their stellar populations.

Findings

High homogeneity in iron content across clusters

Star-to-star variations in light elements observed

Presence of peculiar objects with iron dispersions

Abstract

For several decades, globular clusters have been considered the best example of simple stellar populations, hosting coeval and chemical homogeneous stars. The last decade of spectroscopic and photometric studies has revealed a more complex view of their chemical composition, with a high level of homogeneity in their iron content but star-to-star variations in some light elements. This contribution summarizes the main evidence about the chemical anomalies in the stellar content of the globular clusters, discussing also some peculiar objects with intrinsic dispersions in their iron content.