`Status update' for the AGB scenario for the formation of multiple populations

TL;DR

This paper reviews the twenty-year development of the AGB scenario for multiple star populations, highlighting recent advances in AGB evolution, nucleosynthesis, and observational validations.

Contribution

It summarizes recent progress in understanding massive AGB and super-AGB stars, including explanations for high lithium in certain second-generation stars.

Findings

Validation of the AGB scenario through multiple population properties

Explanation of high lithium abundances in specific star clusters

Advances in modeling AGB and super-AGB stellar evolution

Abstract

The Asymptotic Giant Branch (AGB) scenario for the formation of multiple populations has been quantitatively studied in the course of the latest twenty years, examining the aspects both of nucleosynthesis and of the dynamics of formation of new stars in a cooling flow at the center of the first generation cluster, and of the following N{body evolution. The large complex of these studies finds many validations in the properties of multiple populations. Here I shortly summarize recent accomplishments in the study of the evolution of massive AGBs and super-AGBs including the the explanation of anomalous high lithium abundances in `extreme' second generation stars in wCen and NGC2808.