Multicolor photometry of the giant branch of the open cluster NGC 3532

Abstract

Results obtained at Cerro Tololo and Las Campanas observatories from multicolour photometry (UBV, DDO and CMT₁T₂) of the giant branch of the open cluster NGC 3532 are presented. Two independent criteria have been applied to assign membership probabilities. The results show good agreement with those obtained from previous proper motion studies. Determinations of ultraviolet excesses, cyanogen anomalies, and abundance parameters based on the blue-green and green-red spectral regions, demonstrate that the cluster is chemically homogeneous and has a nearly solar metal content. There is no evidence for convective mixing or mass loss among any of the observed stars. A comparison with the theoretical HR diagram allows us to identify most of the stars as red giants in the core helium burning stage of evolution. The results obtained in this work have been recently published by Clariá and Lapasset (1988, M.N.R.A.S. 235, 1129) and Clariá y Minniti (1988, The Observatory 108, 218).