The Third Catalogue of Nearby Stars with Special Emphasis on Wide Binaries

Thirty-six percent of the 1641 visual components nearer than 22.5 parsecs listed in 1969 were members of systems. Meanwhile for an extension to 25 pc of the Sun about 2000 additional objects are found, however, only 22% of them are known today as members of systems. Angular separations are observed from a few tenths of an arcsec to more than one degree. The widest linear separations at the sphere seem to be larger than 105 astronomical units. The observed frequency distribution of the projected separations for all nearby stars is given and compared with the frequency distribution of more complete subsamples. The 32 presumable systems with the widest separations are discussed with respect to their astrometric and spectroscopic properties.