A dynamical mass for GJ 463 b: A massive super-Jupiter companion beyond the snow line of a nearby M dwarf

We determined the full orbital architecture and true mass of the recently Doppler-detected long-period giant planet GJ 463 b using the HIPPARCOS-Gaia proper motion anomaly in combination with the available radial velocities, constraints from the knowledge of the spectroscopic orbital parameters, and supplementary information from a sensitivity analysis of Gaia Data Release 3 astrometry. We determined an orbital inclination $i_b=152_{-3}^{+2}$ deg (for a prograde orbit) and a mass ratio $q=0.0070\pm 0.0007$, corresponding to a true mass of the companion $M_b=3.6\pm 0.4$ M${}_{\mathrm{J}\mathrm{u}\mathrm{p}}$. True mass determinations for a super-Jupiter companion at intermediate orbital separations beyond the snow line around low-mass stars ($M_{\star }\le 0.5$ M${}_{\odot }$) are a rare occurrence. Its existence is possibly explained in the context of disk-instability models of planet formation.