Abstract

We study the early dynamical evolution of star forming clusters, particularly focused on the effects of the formation timescale.  The timescale for star cluster formation may be long compared to the system's dynamical time so that during this phase, there can be significant dynamical evolution. This is the process we set out to model, here via direct N-body simulations, including realistic primordial binary fractions.  Specifically, we explore how the dynamical evolution of forming clusters depends on the cluster formation timescale and other assumptions that are generally needed for star formation models, such as the degree of primordial mass segregation and binarity. We find that star clusters born slowly can virialize before exhausting/ejecting their natal gas and are more stable against expansion, independent of their initial density.  We can also obtain a considerable amount of runaway stars even in low density environments, whereas they do not form if star formation is fast. Here I show the main results of such modeling and discuss current improvements that include substructured formation and more realistic star cluster formation assumptions.