Washington photometry of open cluster giants: nine old, disc clusters in the third Galactic quadrant

D. GEISLER, J.J. CLARIÁ, D. MINNITI

ASTRONOMICAL JOURNAL

IOP PUBLISHING LTD

Lugar: Londres; Año: 1992 vol. 104 p. 1892 - 1892

0004-6256

ne hundred and thirty six stars associated with nine old open clusters with Galactic longitudes between 215 and 295 degrees have been inestigated with the Washington photometric system. The data yield a luminosity class, temperature, and metal abudance for each star.  The luminosity classification, supplemented with additional membership criteria, is used to separate field stars from cluster giants; definitive membership status is available for virtually the entire sample. Mean metal abundaces for an average of twelve member giants per cluster are determined to an accuracy of of approximately 0.2 dex (standard deviation), including observational and reddening errors.. For the five clusters in common with the recent spectroscopic study by Friel & Janes (A&A, 1992, in press), agreement is generally good, although our metallicities are approximately 0.1 dex lower, on average. Two of the other four clusters, NGC 2324 and NGC 2660, are found to be surprisingly metal-