A TEST OF HIPPARCOS PARALLAXES ON MULTIPLE STARS

The dynamical parallaxes of visual binary stars with reliable orbits s elected from the multiple star catalog are compared with their Hipparc os trigonometric parallaxes. 141 objects with errors in the Hipparcos parallaxes no larger than 2.5 mas are divided into three groups by the quality of their orbits and by the reliability of the Hipparcos compo nent-resolution solutions. The parallaxes have been found to be in goo d agreement for all distant (pi < 15 mas) systems, while at intermedia te distances (pi from 15 to 30 mas) there are cases of large errors in the Hipparcos parallaxes attributable to short-period binaries that h ave been disregarded. The rather large relative proper motions in some wide pairs that follow from the Hipparcos measurements can be explain ed by the orbital motions in close subsystems.