Evaluating `twin' parallaxes for binary stars

Abstract

Employing Gaia DR2 stellar parallaxes, we tried to first evaluate how `twin parallaxes' are compared with Gaia parallaxes. In the meantime, we checked how different is the performance of twin/Gaia parallaxes for binary stars than for single stars. Our study on a sample of Gaia DR2-RAVE DR5 stars shows that for 70% of them, the twin parallaxes agree well with Gaia parallaxes (both for single and binary stars). However, for binary candidates we detected larger scatter between two values than we found for single stars.