Mean absolute proper motions of 94 open clusters from all over the sky, farther than 1 kpc, were determined using the data provided by the Tycho2 Catalogue. Applying the statistical method of Sanders (1971) we asserted the membership of 2021 stars and we determined for the first time mean proper motions of 55 clusters.
A comparison of our results with those of BDW showed that both sets are in agreement. In a few cases with discrepant results NGC 2360, NGC 2244, NGC 6531 and Trumpler 15, we suggest that the results from BDW are the correct ones. However for the clusters NGC 1893 and NGC 5138 we could show that the differences were real differences between Tycho2 and Hipparcos, or due to the too small numbers of stars considered by BDW. The comparison makes us confident that the proper motions derived for the first time are correct, and provide a useful confirmation of BDW results, using a larger sample of stars.
Acknowledgements
Extensive use has been made of the SIMBAD and BDA databases. This project is supported by FAPESP (grant number 99/11781-4).
Copyright ESO 2002