Evolution of second generation stars in stellar disks of globular and nuclear clusters: Omega Centauri as a test case

TL;DR

This study uses N-body simulations to explore how second-generation stars in flattened disk structures within globular clusters evolve, revealing kinematic signatures that help understand their origins and dynamical history.

Contribution

It demonstrates through simulations that second-generation stars formed in disks leave detectable kinematic signatures, aiding in understanding their formation and evolution in globular clusters.

Findings

Disk-like second-generation stars produce anisotropic kinematic signatures.

Such stars exhibit lower velocity dispersions compared to first-generation populations.

Simulations suggest long-term dynamical evolution preserves these signatures.

Abstract

Globular clusters (GCs) and many nuclear clusters (NCs) show evidence for hosting multiple generations of stellar populations. Younger stellar populations in NCs appear to reside in disk like structures, including the nuclear cluster in our own Galactic center as well as in M31. Kinematic studies of the anomalous globular cluster Omega Centauri, thought to possibly be a former dwarf galaxy (or a galactic nucleus), show evidence for its hosting of a central, kinematically cold disk component. These observations suggest that formation of second (or multiple) generation stars may occur in flattened disk like structures. Here we use detailed N-body simulations to explore the possible evolution of such stellar disks, embedded in globular clusters. We follow the long term evolution of a disk like structure similar to that observed in Omega Centauri and study its properties. We find that a stellar-disk like origin for second generation stellar populations can leave behind significant kinematic signatures in properties of the clusters, including an anisotropic distribution, and lower velocity dispersions, which can be used to constrain the origin of second generations stars and their dynamical evolution.