IAU Commission 37 "Star Clusters and Associations" Legacy report

TL;DR

This report summarizes recent progress in understanding star clusters and associations, emphasizing their role in galaxy evolution, star formation, and stellar evolution, based on scientific results from the last decade.

Contribution

It provides a comprehensive overview of recent advances in star cluster research, highlighting new insights into their formation, evolution, and their importance in galactic studies.

Findings

Star clusters are key to understanding galaxy formation and evolution.

Recent studies have improved knowledge of star formation in dense environments.

Star cluster properties help derive fundamental stellar quantities like the initial mass function.

Abstract

It is widely accepted that stars do not form in isolation but result from the fragmentation of molecular clouds, which in turn leads to star cluster formation. Over time, clusters dissolve or are destroyed by interactions with molecular clouds or tidal stripping, and their members become part of the general field population. Star clusters are thus among the basic building blocks of galaxies. In turn, star cluster populations, from young associations and open clusters to old globulars, are powerful tracers of the formation, assembly, and evolutionary history of their parent galaxies. Although their importance had been recognised for decades, major progress in this area has only become possible in recent years, both for Galactic and extragalactic cluster populations. Star clusters are the observational foundation for stellar astrophysics and evolution, provide essential tracers of galactic structure, and are unique stellar dynamical environments. Star formation, stellar structure, stellar evolution, and stellar nucleosynthesis continue to benefit and improve tremendously from the study of these systems. Additionally, fundamental quantities such as the initial mass function can be successfully derived from modelling either the H-R diagrams or the integrated velocity structures of, respectively, resolved and unresolved clusters and cluster populations. Star cluster studies thus span the fields of Galactic and extragalactic astrophysics, while heavily affecting our detailed understanding of the process of star formation in dense environments.This report highlights science results of the last decade in the major fields covered by IAU Commission 37: Star clusters and associations.