Lithium and proton-capture elements in globular clusters: implications for multiple population scenarios

TL;DR

This paper reviews the complex behavior of lithium and proton-capture elements in globular cluster stars, highlighting how lithium's unexpected presence challenges existing models of stellar pollution and multiple population formation.

Contribution

It provides a comprehensive review of recent findings on lithium and proton-capture elements in globular clusters, emphasizing the implications for multiple population scenarios.

Findings

Lithium's presence in processed material challenges hot H-burning models.

Surprising observational results complicate the understanding of stellar pollution.

Implications for the formation and evolution of multiple populations in globular clusters.

Abstract

In the multiple population framework, a number of studies have been accomplished in order to explore the behaviour of lithium with proton-capture element abundances (e.g., Na, O, Al) in globular cluster stars. Lithium offers perhaps one of the most severe constraints on the stellar source of internal pollution in these complex systems. Given its vulnerability, we expect that material processed via the hot H-burning, re-cycled in the formation of the subsequent generation(s), is free of Li. However, Nature breaks our expectations. In this contribution, we will review the current status of this field, by examining the controversial, surprising results and implications.