CCD astrometry and UBV photometry of visual binaries ^*

II. Visual double stars with mainly G - type primaries and relatively small angular separation

Royal Belgian Observatory, Ringlaan 3, B-1180 Ukkel, Brussels, Belgium

Received: 16 October 1997
Accepted: 8 December 1997

Abstract

Differences of magnitude and and colours, as well as separations and position angles of 42 relatively close double stars are presented. The selection criteria of our sample are: the relatively small separation (between 2.5 and 5 arcseconds), magnitude difference under 1.25 mag, and mainly G-type primaries. The CCD observations, performed at the 90 cm Dutch telescope at ESO, were made using the Bessel U, B and V filters; the astrometry was done in the V filter only. From the analysis of the photometric data we conclude that 16 binaries in our sample have components with practically the same T_eff, since they have almost the same colours; one binary has components with identical characteristics. We also note the good internal accuracy of the astrometric CCD measurements.