The Evolution of Protoplanetary Disks in the Arches Cluster

TL;DR

This study models the evolution of protoplanetary discs in the hostile environment of the Arches starburst cluster, showing that stellar encounters significantly destroy discs and predicting observable tidal tail features.

Contribution

It provides the first detailed simulation of disc evolution in a starburst cluster, highlighting the impact of stellar encounters and predicting observable tidal tail signatures.

Findings

One third of circumstellar discs are destroyed within 2.5 Myr in the cluster core.

Encounters preferentially affect the least and most massive stars.

A second, disc-poor tidal tail is predicted to be observable.

Abstract

Most stars form in a cluster environment. These stars are initially surrounded by discs from which potentially planetary systems form. Of all cluster environments starburst clusters are probably the most hostile for planetary systems in our Galaxy. The intense stellar radiation and extreme density favour rapid destruction of circumstellar discs via photoevaporation and stellar encounters. Evolving a virialized model of the Arches cluster in the Galactic tidal field we investigate the effect of stellar encounters on circumstellar discs in a prototypical starburst cluster. Despite its proximity to the deep gravitational potential of the Galactic centre only a moderate fraction of members escapes to form an extended pair of tidal tails. Our simulations show that encounters destroy one third of the circumstellar discs in the cluster core within the first 2.5 Myr of evolution, preferentially affecting the least and most massive stars. A small fraction of these events causes rapid ejection and the formation of a weaker second pair of tidal tails that is overpopulated by disc-poor stars. Two predictions arise from our study: (i) If not destroyed by photoevaporation protoplanetary discs of massive late B- and early O-type stars represent the most likely hosts of planet formation in starburst clusters. (ii) Multi-epoch K- and L-band photometry of the Arches cluster would provide the kinematically selected membership sample required to detect the additional pair of disc-poor tidal tails.