MASS RATIOS IN MULTIPLE STAR SYSTEMS
Recently a catalogue of 612 physical multiple stars was published by Tokovinin. The systems are generally hierarchical, i.e. they consist of binaries of different hierarchy levels. We have studied the mass ratios of the hierarchical binaries as a diagnostic of the origin of the multiple systems. The threebody statistical break-up theory is used to obtain likely mass ratio distributions in dynamically strongly interacting systems. A comparison with the catalogue data shows good agreement between theory and observations. This tells us that the multiple stars of the catalogue are not primordial but their properties are results of dynamical interactions where the three-body ejection process plays a key role.