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Structure and stellar content analysis of the open cluster M 11 with 2MASS photometry

¹ Departamento de Física, ICEx, UFMG, CP 702, 30123-970 Belo Horizonte, MG, Brazil e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
² Departamento de Astronomia, IF-UFRGS, CP 15051, 91501-970 Porto Alegre, RS, Brazil

Received: 6 May 2005
Accepted: 3 July 2005

Abstract

An overall analysis of the structure and stellar content of M 11 is presented, thanks to the wide-angle 2MASS spatial coverage. We derive photometric and structural parameters and discuss the spatial dependance of the luminosity and mass functions. Photometric parameters basically agree with previous ones mostly based on the optical. We obtained a core radius of 1.23 pcand a tidal radius of 29 pc. In particular, the cluster is populous enough so thatthe tidal radius could be obtained by fitting the three-parameter King profileto the radial distribution of stars.We analyzed the spatial distribution of mass functions, finding that the slope changesfrom -0.73 in the core to +2.88 in the outer halo. The spatial distribution ofmass function slopes derived from 2MASS agrees with that derived from optical CCD data, which further confirms the reliability of 2MASS data for future analyses of this kind at comparable observational limits. We detect mass segregation up todistances from the center of≈. We emphasize that the mass function slope in the core is flatter than anywhere else as a consequenceof mass segregation. The derived total cluster mass is≈.