Helium variations in Galactic and extragalactic Globular Clusters

TL;DR

This paper reviews recent helium variation measurements in Galactic and extragalactic globular clusters, providing insights into multiple population formation, environmental effects, and early galactic evolution.

Contribution

It offers updated helium enrichment estimates across numerous globular clusters, enhancing understanding of their formation and environmental influences.

Findings

Helium variations vary among globular clusters.

Environmental factors influence multiple population formation.

Helium enrichment levels inform early galaxy formation models.

Abstract

The recent measurements of internal variations of helium in Galactic and extragalactic Globular Clusters (GCs) set binding constraints to the models of formation of Multiple Populations (MPs) in GCs, and gave rise, at the same time, to crucial questions related with the influence of the environment on MP formation as well as with the role played by GCs in the early galactic formation. We present the most recent estimates of helium enrichment in the main populations of a large sample of Galactic and extragalactic GCs.