Journal Article

A search for mass segregation of stars and brown dwarfs in ρ Ophiuchi

Richard J. Parker, Thomas Maschberger and Catarina Alves de Oliveira

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 426, issue 4, pages 3079-3085
Published in print November 2012 | ISSN: 0035-8711
Published online November 2012 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2012.21790.x
A search for mass segregation of stars and brown dwarfs in ρ Ophiuchi

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Abstract

We apply two different algorithms to search for mass segregation to a recent observational census of the ρ Ophiuchi star-forming region. First, we apply the ΛMSR method, which compares the minimum spanning tree (MST) of a chosen subset of stars to MSTs of random subsets of stars in the cluster, and determine the mass segregation ratio, ΛMSR. Secondly, we apply the m–Σ method, which calculates the local stellar surface density around each star and determines the statistical significance of the average surface density for a chosen mass bin compared to the average surface density in the whole cluster. Using both methods, we find no indication of mass segregation (normal or inverse) in the spatial distribution of stars and brown dwarfs in ρ Ophiuchi. Although ρ Ophiuchi suffers from high visual extinction, we show that a significant mass segregation signature would be detectable, albeit slightly diluted, despite dust obscuration of centrally located massive stars.

Keywords: methods: data analysis; brown dwarfs; stars: low-mass; galaxies: star clusters: individual: ρ Ophiuchi

Journal Article.  5055 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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