Young massive star clusters: Achievements and challenges

TL;DR

This paper reviews the current understanding of young massive star clusters, highlighting key uncertainties in their formation, evolution, and mass estimation, and emphasizes the need for collaborative efforts across disciplines.

Contribution

It critically assesses current knowledge on initial conditions, binary fractions, and mass functions of star clusters, proposing integrated approaches for future progress.

Findings

Initial substructure influences cluster evolution.

Uncertainties in binary fraction and mass function shape.

Challenges in accurate dynamical mass estimates.

Abstract

In spite of significant recent and ongoing research efforts, most of the early evolution and long-term fate of young massive star clusters remain clouded in uncertainties. Here, I discuss our understanding of the initial conditions of star cluster formation and the importance of initial substructure for the subsequent dynamical-evolution and mass-segregation timescales. I also assess our current understanding of the (initial) binary fraction in star clusters and the shape of the stellar initial mass function at the low-mass end in the low-metallicity environment of the Large Magellanic Cloud. Finally, I question the validity of our assumptions leading to dynamical cluster mass estimates. I conclude that it seems imperative that observers, modellers and theorists combine efforts and exchange ideas and data freely for the field to make a major leap forward.