Comparison of Gaia and Hipparcos parallaxes of close visual binary stars and the impact on determinations of their masses

Abstract Precise measurement of the fundamental parameters stellar systems, including mass and radius, depends critically on how well distances are known. Astrometry from space provides parallax measurements unprecented accuracy, which can be derived, initially Hipparcos mission, with a further refinement that analysis provided by van Leeuwen in 2007. The publication Gaia DR2 catalogue promises dramatic improvement available data. We have recalculated dynamical masses sample 1 700 close visual binary stars using compared results derived both original enhanced show yields to those DR2, but latter significantly more accurate. consider impact parallaxes our understanding binaries.