EDP Sciences
Free Access
Volume 478, Number 2, February I 2008
Page(s) 667 - 674
Section Online catalogs and data
DOI https://doi.org/10.1051/0004-6361:20077885

A&A 478, 667-674 (2008)
DOI: 10.1051/0004-6361:20077885

Stars and brown dwarfs in the $\sigma$ Orionis cluster: the Mayrit catalogue

J. A. Caballero

Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
    e-mail: caballero@astrax.fis.ucm.es

(Received 15 May 2007 / Accepted 22 October 2007 )

Context.The young $\sigma$ Orionis cluster is an indispensable basis for understanding the formation and evolution of stars, brown dwarfs, and planetary-mass objects. Our knowledge of its stellar population is, however, incomplete.
Aims.I present the Mayrit catalogue, which comprises most of the stars and high-mass brown dwarfs in the cluster.
Methods.The basis of this work is an optical-near infrared correlation between the 2MASS and DENIS catalogues in a circular area of radius 30 arcmin centred on the OB-type binary $\sigma$ Ori AB. The analysis is supported by a bibliographic search of confirmed cluster members with features of youth and by additional X-ray, mid-infrared, and astrometric data.
Results.I list 241 $\sigma$ Orionis stars and brown dwarfs with known features of youth, 97 candidate cluster members (40 are new), and 115 back- and foreground sources in the survey area. The 338 cluster members and member candidates constitute the Mayrit catalogue.
Conclusions.This catalogue is a suitable input for studying the spatial ditribution, multiplicity, properties and frequency of discs, and the complete mass function of $\sigma$ Orionis.

Key words: astronomical data bases: miscellaneous -- stars: low-mass, brown dwarfs -- Galaxy: open clusters and associations: individual: $\sigma$ Orionis

© ESO 2008