SCYON Abstract

Received on October 25 2002

Subsystem of open clusters in post Hipparcos epoch.
Structure parameters and proper motions

AuthorsN.V. Kharchenko1, L.K. Pakulyak1 and A.E. Piskunov2
Affiliation1 Main Astronomical Observatory, 27 Academica Zabolotnogo Str., 03680 Kiev, Ukraine
2 Institute of Astronomy of the Russian Acad. Sci., 48 Pyatnitskaya Str., Moscow 109017, Russia
To appear inAstronomy Reports
Contactpiskunov@inasan.rssi.ru
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Abstract

We study wide neighborhoods of 401 open clusters from data of all sky high precision homogeneous catalogue ASCC-2.5. More than 28'000 possible members (including about 12'500 most probable ones) have been selected on the basis of proper motion and photometric criteria. Angular and linear radii of cluster cores and coronae, which by more than twice exceed published previously values, have been determined from stellar counts in ASCC-2.5 and USNO-A2.0 catalogues. The segregation of cluster members with their brightness (different degree of their concentration to cluster centers) was revealed. The average cluster proper motions in the Hipparcos system were determined for 401 open clusters (for 183 of them for the first time). The cluster distances based on color-magnitude diagrams of selected members were determined for the first time for 118 clusters.