SCYON Abstract

Received on September 20 2006

A dynamical origin for early mass segregation in young star clusters

AuthorsS. McMillan (1), E. Vesperini (1), and S. Portegies Zwart (2)
Affiliation
(1) Department of Physics, Drexel University, Philadelphia, PA 19104, USA
(2) Astronomical Institute "Anton Pannekoek" and Section Computational Science, University of Amsterdam, Kruislaan 403, 1098SJ Amsterdam, the Netherlands
Submitted toAstrophysical Journal
Contactsteve@physics.drexel.edu
URLhttp://einstein.physics.drexel.edu/directory/faculty/mcmillan.html
Links

Abstract

Some young star clusters show a degree of mass segregation that is inconsistent with the effects of standard two-body relaxation from an initially unsegregated system without substructure, in virial equilibrium, and it is unclear whether current cluster formation models can account for this degree of initial segregation in clusters of significant mass. In this Letter we demonstrate that mergers of small clumps that are either initially mass segregated, or in which mass segregation can be produced by two-body relaxation before they merge, generically lead to larger systems which inherit the progenitor clumps' segregation. We conclude that clusters formed in this way are naturally mass segregated, accounting for the anomalous observations and suggesting that this process of prompt mass segregation due to initial clumping should be taken fully into account in constructing cluster dynamical models.