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

TL;DR

This paper accurately determines the true mass and orbital parameters of GJ 463 b, a super-Jupiter beyond the snow line of a nearby M dwarf, using combined astrometric and radial velocity data.

Contribution

It presents the first true mass measurement of a super-Jupiter at intermediate separation around a low-mass star, confirming its nature and supporting disk-instability formation models.

Findings

True mass of GJ 463 b is 3.6 ± 0.4 M_Jup.

Orbital inclination is approximately 152 degrees.

Supports disk-instability as a formation mechanism.

Abstract

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 $i_b=152^{+2}_{-3}$ deg (for a prograde orbit) and a mass ratio $q=0.0070\pm0.0007$, corresponding to a true mass of the companion $M_b=3.6\pm0.4$ M$_\mathrm{Jup}$. True mass determinations for a super-Jupiter companion at intermediate orbital separations beyond the snow line around low-mass stars ($M_\star\leq 0.5$ M$_\odot$) are a rare occurrence. Its existence is possibly explained in the context of disk-instability models of planet formation.