Table 5:
Candidate and confirmed astrometric binaries in the Hipparcos catalogue. For each subgroup we list the number
of known members, the number of stochastic (X); orbital (O); acceleration (G); component (C); and suspected (S) binaries in the Hipparcos catalogue. For each (S) binary we list between brackets how many of these are also (X)-flagged. The last three columns list the "astrometric binary fraction'' - including the (X), (O), (G) binaries - without the (S) binaries and with the (S) binaries included, and the Hipparcos "visual'' binary fraction, for the (C) binaries only. (V) binaries are not present in Sco OB2.