Reading the book: from "chemical anomalies" to "standard composition" of globular clusters

TL;DR

This paper reviews how high-resolution spectroscopy has advanced our understanding of the complex formation and multiple stellar populations in globular clusters, emphasizing chemical composition evidence.

Contribution

It highlights the transition from single to multiple stellar populations in GCs based on spectroscopic data and discusses recent observational findings.

Findings

Chemical anomalies are key to identifying multiple populations.

High-resolution spectroscopy reveals complex formation histories.

Recent large-sample observations support multiple stellar generations.

Abstract

It is now commonly accepted that globular clusters (GCs) have undergone a complex formation and that they host at least two stellar generations. This is a recent paradigm and is founded on both photometric and spectroscopic evidence. We concentrate on results based on high-resolution spectroscopy and on how we moved from single to multiple stellar populations concept for GCs. We underline that the peculiar chemical composition of GC stars is fundamental in establishing the multiple populations scenario and briefly outline what can be learned from observations. Finally, recent observational results on large samples of stars in different evolutionary phases are discussed.