Mass segregation in M67 with 2MASS

Abstract

We make use of the homogeneity, depth and sky coverage of the 2MASS catalogue to study spatial variations of the stellar luminosity function in the intermediate age cluster M67 (NGC2682). We find that the central region (R < 3:30) has a depletion of G0 and G5 stars with respect to the intermediate annulus (3:30 < R < 7:40) and the halo (120 < R < 240). In the non-eroded part of the mass function the slope is steeper in the intermediate annulus than in the central region, suggesting an enhancement of F 0 stars with respect to turno and A5 stars in the latter zone. In the halo, the G0–G 5 stars are not depleted as compared to the central region, but the overall mass function slope is rather shallow. This suggests that the halo is enriched in low mass stars, transferred there from the inner parts as a consequence of the internal dynamical evolution, but tidal losses to the Galactic field have also been important.