The Role of N-body Dynamics in Early Cluster Evolution

Abstract

In the previous chapters we have reviewed simulations which aim to provide the greatest level of ‘realism’ through the modelling of hydrodynamical (and magneto-hydrodynamical) processes. Such simulations are, naturally, limited in their scope due to computational requirements and even the most expensive of these will typically only model the first $\sim$0.5 Myr of a star cluster. In this chapter we review methods to extend the lifetime of star cluster simulations to beyond $\sim$10 Myr by viewing the process as one of a purely stellar dynamical nature—so-called N-body simulations. We present an overview of how these simulations are particularly useful for exploring processes that occur over a number of dynamical timescales and which are driven by so-called two-body relaxation effects. We also discuss how such effects are important in driving cluster core collapse as well as determining the properties of surviving binary populations, in addition to what role the natal gas of star clusters plays in the ultimate survival of clusters on larger timescales.