Open clusters in 2MASS photometry II. Mass Function and Mass Segregation
  This is a continuation of our study of open clusters based on the 2--Micron
All Sky Survey photometry. Here we present the results of the mass function
analysis for 599 known open clusters in the Milky Way. The main goal of this
project is a study of the dynamical state of open clusters, the mass
segregation effect and an estimate of the total mass and the number of cluster
members. We noticed that the cluster size (core and overall radii) decreases
along dynamical evolution of clusters. The cluster cores evolve faster than the
halo regions and contain proportionally less low-mass stars from the beginning
of the cluster dynamical evolution. We also noticed, that the star density
decreases for the larger clusters. Finally, we found an empirical relation
describing the exponential decrease of the mass function slope with the
dynamical evolution of clusters.
