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Astron. Astrophys. 357, 149-152 (2000)

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Proper motion and membership determination in the young open cluster NGC 1662

W.S. Dias, R. Boczko, J.I.B. Camargo, R. Teixeira and P. Benevides-Soares

Universidade de São Paulo, Dept. de Astronomia, CP 3386, São Paulo 01060-970, Brazil (wilton@iagusp.usp.br)

Received 1 February 2000 / Accepted 13 March 2000


Relative proper motions and cluster membership probabilities of 30 stars within an area of [FORMULA] of diameter centered in the open cluster NGC 1662 ([FORMULA], [FORMULA]) are determined by combining positions of stars observed by the Valinhos CCD meridian circle with those from other astrometric catalogues.

Our basic source for first epoch of stars brighter than B[FORMULA]13 magnitudes is the AC2000 Catalogue, which provides a time baseline of about 90 years, whereas the USNO-A2.0 Catalogue is used for fainter stars, providing a time baseline of about 40 years in this region.

Average accuracies in proper motion of 2 mas/yr and 7 mas/yr are achieved, respectively, when the AC2000 or the USNO-A2.0 is used.

Membership determination is obtained by applying the Zhao & He (1990) method. The cluster proper motion was found to be ([FORMULA]) mas/yr in right ascension and ([FORMULA]) mas/yr in declination.

Key words: astrometry – Galaxy: open clusters and associations: individual: NGC 1662

Send offprint requests to: W.S. Dias

© European Southern Observatory (ESO) 2000

Online publication: May 3, 2000