A new model for simulating circumstellar dynamics in young stellar clusters

Abstract

ABSTRACT Simulations of angular momentum transfer from a surrounding star cluster to distant planetesimals orbiting around a cluster member have been used since more than two decades to study the formation of small body populations in the outskirts of the Solar system (Oort Cloud and sednoids). We present a new model for these interactions, for the first time combining two features of earlier works: (1) a self-consistent treatment of cluster evolution based on N-body simulations, and (2) a treatment of circumstellar dynamics as resulting from a combination of a smooth tidal field representing the whole cluster and close encounters by individual cluster members. The model is expected to be both flexible, accurate, and efficient in terms of CPU time and hence a suitable tool when simulating large or long-lived clusters or when many independent runs are needed for statistical significance. We describe the model in detail and give examples of its outputs. These are of relevance not only for the perihelion extraction of small bodies but also for the stability properties of young or nascent planetary systems or protoplanetary discs.