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A survey of Probable Open Cluster Remnants in the Galactic disk. S. Villanova & G. Carraro, Universita’ di Padova. Collinder 21. De la Fuente Marcos, 1997, 1998, 1999. METHOD:. • photometric catalogs of stars in Possible OCRs.
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A survey of Probable Open Cluster Remnants in the Galactic disk S. Villanova & G. Carraro, Universita’ di Padova
Collinder 21 De la Fuente Marcos, 1997, 1998, 1999
METHOD: • photometric catalogs of stars in Possible OCRs. • astrometric data from UCAC2/USNO-B1 catalogs. • radial velocity from high resolution spectra Probe the nature of the aggregate, its membership, the dynamical status, age, distance and binary fraction.
FINAL GOALS: . Provide observational constraints for Nbody models of clusters evolution and dissolution Discover remnants of old clusters, to increase the sample of very old open clusters in the Galactic disk
NGC 1901 : a genuine cluster remnant A DSS Map Vector point diagram
Age = 0.5±0.1 Gyr Member number = 11 distance = 450±30 pc = 2.4±0.4 km/sec mass = 40 solar masses IMF slope = -1.65 binaries number: 2±1 Radial velocities CMD NGC 1901: cont.
An example of spectra Present-day Mass function NGC 1901: cont.
NGC 5385: a false detection A DSS map Vector point diagram
Simply a chance overdensity along the line sight….. Radial velocities CMD NGC 5385: cont.
CONCLUSIONS & FUTURE PERSPECTIVES CONCLUSIONS & FUTURE PERSPECTIVES • Build up a sample of OCRs as an observational workbench for N-body models aiming at understanding cluster evolution, evaporation, and the formation of field stars • Enlarge the sample of old clusters to probe the chemical and dynamical evolution of the Galactic disk during its infancy