We study the multiplicity function and physical properties of single, double, and multiple stellar systems in the solar neighbourhood (r < 10 pc), using a new preliminary machine–readable version of the Gliese & Jahreiss Catalogue (1991).
The ratio of (n+l)-ple to n-ple systems is a constant fraction of about 1/4 for n =1, 2, 3, 4. The luminosity function f(M) for primaries in binaries has an additional peak at M є (6m,8m) that is absent in f(M) for single stars and secondary components. A significant correlation between the absolute magnitudes M
1 and M
2 of the components in binaries takes place.