Open AccessA Dynamical Origin for Early Mass Segregation in Young Star Clusters
Author(s) -
Stephen L. W. McMillan,
Enrico Vesperini,
Simon Portegies Zwart
Publication year - 2007
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/511763
Subject(s) - substructure , mass segregation , merge (version control) , cluster (spacecraft) , physics , astrophysics , virial theorem , relaxation (psychology) , star formation , star cluster , stars , galaxy , structural engineering , computer science , engineering , information retrieval , programming language , psychology , social psychology
Some young star clusters show a degree of mass segregation that isinconsistent with the effects of standard two-body relaxation from an initiallyunsegregated system without substructure, in virial equilibrium, and it isunclear whether current cluster formation models can account for this degree ofinitial segregation in clusters of significant mass. In this Letter wedemonstrate that mergers of small clumps that are either initially masssegregated, or in which mass segregation can be produced by two-body relaxationbefore they merge, generically lead to larger systems which inherit theprogenitor clumps' segregation. We conclude that clusters formed in this wayare naturally mass segregated, accounting for the anomalous observations andsuggesting that this process of prompt mass segregation due to initial clumpingshould be taken fully into account in constructing cluster dynamical models.Comment: 13 pages, 4 figures, submitted to ApJ
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