Multiple stellar populations in Galactic globular clusters: observational evidence

TL;DR

Recent observational evidence from photometric and spectroscopic studies confirms that many Galactic globular clusters host multiple stellar populations, challenging the traditional view of these clusters as simple stellar populations.

Contribution

This paper summarizes the observational evidence for multiple stellar populations in Galactic globular clusters, highlighting the shift from the single-population paradigm.

Findings

Multiple populations identified in color-magnitude diagrams

Star-to-star abundance variations observed

Clusters host distinct sub-populations

Abstract

An increasing number of both photometric and spectroscopic observations over the last years have shown the existence of distinct sub-populations in many Galactic globular clusters and shattered the paradigm of globulars hosting single, simple stellar populations. These multiple populations manifest themselves in a split of different evolutionary sequences in the cluster color-magnitude diagrams and in star-to-star abundance variations. In this paper we will summarize the observational scenario.