We derive photometric , structural and dynamical evolution-related parameters of 11 nearby open clusters with ages in the range 70 Myr to 7 Gyr and masses in the range \approx 400 M _ { \odot } to \approx 5 300 M _ { \odot } .
The clusters are homogeneously analysed by means of J , H and K _ { S } 2MASS photometry , which provides spatial coverage wide enough to properly take into account the contamination of the cluster field by Galaxy stars .
Structural parameters such as core and limiting radii are derived from the background-subtracted radial density profiles .
Luminosity and mass functions ( MFs ) are built for stars later than the turnoff and brighter than the 2MASS PSC 99.9 % completeness limit .
The total mass locked up in stars in the core and the whole cluster , as well as the corresponding mass densities , are calculated by taking into account the observed stars ( evolved and main sequence ) and extrapolating the MFs down to the H-burning mass limit , 0.08 M _ { \odot } .
We illustrate the methods by analysing for the first time in the near-infrared the populous open clusters NGC 2477 and NGC 2516 .
For NGC 2477 we derive an age of 1.1 \pm 0.1 Gyr , distance from the Sun \mbox { $ d _ { \odot } $ } = 1.2 \pm 0.1 kpc , core radius \mbox { $ R _ { core } $ } = 1.4 \pm 0.1 pc , limiting radius \mbox { $ R _ { lim } $ } = 11.6 \pm 0.7 pc and total mass \mbox { $ m _ { tot } $ } \approx ( 5.3 \pm 1.6 ) \times 10 ^ { 3 } M _ { \odot } .
Large-scale mass segregation in NGC 2477 is reflected in the significant variation of the MF slopes in different spatial regions of the cluster , and in the large number-density of giant stars in the core with respect to the cluster as a whole .
For NGC 2516 we derive an age of 160 \pm 10 Myr , \mbox { $ d _ { \odot } $ } = 0.44 \pm 0.02 kpc , \mbox { $ R _ { core } $ } = 0.6 \pm 0.1 pc , \mbox { $ R _ { lim } $ } = 6.2 \pm 0.2 pc and \mbox { $ m _ { tot } $ } \approx ( 1.3 \pm 0.2 ) \times 10 ^ { 3 } M _ { \odot } .
Mass-segregation in NGC 2516 shows up in the MFs .
Six of the 11 clusters present a slope break in the MF occurring at essentially the same mass as that found for the field stars in Kroupa ’ s universal IMF .
The MF break is not associated to cluster mass , at least in the clusters in this paper .
In two clusters the low-mass end of the MF occurs above the MF break .
However , in three clusters the MF break does not occur , at least for the mass range m \geq 0.7 \mbox { $ M _ { \odot } $ } .
One possibility is dynamical evolution affecting the MF slope distribution .
We also search for relations of structural and evolutionary parameters with age and Galactocentric distance .
The main results for the present sample are : ( i ) cluster size correlates both with age and Galactocentric distance ; ( ii ) because of size and mass scaling , core and limiting radii , and core and overall mass correlate ; ( iii ) massive ( m \geq 1 000 M _ { \odot } ) and less-massive clusters follow separate correlation paths on the plane core radius and overall mass ; ( iv ) MF slopes of massive clusters are restricted to a narrow range , while those of the less-massive ones distribute over a wider range .
Core and overall MF flattening is related to the ratio ( \tau ) of age to relaxation time .
For large values of \tau the effects of large-scale mass segregation and low-mass stars evaporation can be observed in the MFs .
In this sense , \tau appears to characterize the evolutionary state of the clusters .
We conclude that appreciable slope flattenings in the overall MFs of the less-massive clusters take \sim 6 times longer to occur than in the core , while in the massive clusters they take a time \sim 13 times longer .
We investigate cluster parameters equivalent to those determining the fundamental plane of ellipticals .
These parameters are : overall mass , projected mass density and core radius .
We conclude that in the present sample there is evidence of a fundamental plane .
Larger samples are necessary to pin down this issue .