The structure and dynamics of the open cluster M11

A data base of the proper motions (PM) and photometric measurements of M11 open cluster members is presented and discussed. A total of 1890 stars were scanned for PM data and over 1000 for V and B-V data. The study was conducted to define procedures for assigning open cluster membership status to stars. The color-magnitude diagrams obtained were used to validate membership probabilities based on the ratio of the cluster distribution frequency to the sum of the cluster and field frequencies. The luminosities in M11 varied from inner to outer regions due to mass-segregation phenomena. The M11 radial surface-density profiles were matched well with multi-mass King models featuring energy equipartitioning and anisotropy in outer areas. The distribution of red giants was typical of 2.8 solar mass stars, although the giants' mass loss rates are as yet unknown.