How to separate binary and optical stellar pairs? I have list of stellar pairs from The Washington Double Star Catalog (WDS), i.e. I have next parameters:


angular separations
position angles
stellar magnitudes of both components


Additionally I have GAIA DR2 parallaxes (and other parameters) from SIMBAD database. How to distinguish between binary and optical stellar pairs?
If they are both in the Gaia DR2 catalogue, then a physical binary should have components with similar parallax and proper motion.