Orbital Solution and Dynamical Masses for the Nearby Binary System Gls 67 AB

TL;DR

This study combines over a century of spectroscopic and astrometric data to precisely determine the orbital parameters and masses of the nearby binary system Gls 67 AB, highlighting the importance of historical observations.

Contribution

It provides a comprehensive orbital solution and dynamical masses for Gls 67 AB by integrating diverse observational data, and offers a corrected, more accurate parallax estimate.

Findings

Masses of primary and secondary are 0.95 and 0.254 solar masses.

Derived parallax is 79.08 mas, correcting Gaia DR3 bias.

Limited by few relative position measurements.

Abstract

We report spectroscopic observations of the nearby, 19.5 yr binary system Gls 67 AB 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 $0.95 \pm 0.11$ and $0.254 \pm 0.019~M_{\odot}$, respectively, as well as a more accurate trigonometric parallax of $79.08 \pm 0.63$ mas that 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.