The early dynamical evolution of cool, clumpy star clusters
Abstract
Observations and theory both suggest that star clusters form sub-virial (cool) with highly sub-structured distributions. We perform a large ensemble of N-body simulations of moderate-sized (N=1000) cool, fractal clusters to investigate their early dynamical evolution. We find that cool, clumpy clusters dynamically mass segregate on a short timescale, that Trapezium-like massive higher-order multiples are commonly formed, and that massive stars are often ejected from clusters with velocities > 10 km/s (c.f. the average escape velocity of 2.5 km/s). The properties of clusters also change rapidly on very short timescales. Young clusters may also undergo core collapse events, in which a dense core containing massive stars is hardened due to energy losses to a halo of lower-mass stars. Such events can blow young clusters apart with no need for gas expulsion. The warmer and less substructured a cluster is initially, the less extreme its evolution.
Keywords
Cite
@article{arxiv.1004.5244,
title = {The early dynamical evolution of cool, clumpy star clusters},
author = {Richard J. Allison and Simon P. Goodwin and Richard J. Parker and Simon F. Portegies Zwart and Richard de Grijs},
journal= {arXiv preprint arXiv:1004.5244},
year = {2015}
}
Comments
Accepted for publication in MNRAS; supplementary material can be downloaded at http://sgoodwin.staff.shef.ac.uk/all_plots.pdf.gz