Orbital solution and dynamical masses for the nearby binary system GJ 67 AB

Abstract

ABSTRACT We report spectroscopic observations of the nearby, 19.5-yr binary system GJ 67AB spanning more than 35 yr. We carry out a global orbital solution combining our radial-velocity measurements with others from the literature going back more than a century, and with all other available astrometric observations. The latter include measurements of the relative position as well as the Hipparcos intermediate data and photographic observations tracing the motion of the photocentre. We derive masses for the primary and the M-dwarf secondary of 0.95 ± 0.11 and 0.254 ± 0.019 M⊙, respectively, as well as a more accurate trigonometric parallax of 79.08 ± 0.63 mas, which accounts for the orbital motion. We provide evidence suggesting that the much smaller parallax from Gaia DR3 is biased. The precision in the masses remains limited mainly by the still few measurements of the relative position.