  Context. The observed scarcity of brown dwarfs in close orbits (within 10 au)
around solar-type stars poses significant questions about the origins of these
substellar companions. These questions impact our broader understanding of
planetary formation processes. However, to resolve these formation mechanisms,
accurate observational constraints are essential. Most of the brown dwarfs have
been discovered by radial velocity surveys, but this method introduces
uncertainties due to its inability to determine the orbital inclination,
leaving the true mass-and thus their true nature-unresolved. This highlights
the crucial role of astrometric data, helping us distinguish between genuine
brown dwarfs and stars. Aims. We aim to refine the mass estimates of massive
companions to solar-type stars, mostly discovered through radial velocity
measurements and subsequently validated using Gaia DR3 astrometry, to gain a
clearer understanding of their true mass and occurrence rates. Methods. We
selected a sample of 31 sources with substellar companion candidates validated
by Gaia DR3 and with available radial velocities. Using the Gaia DR3 solutions
as prior information, we performed an MCMC fit with the available radial
velocity measurements to integrate these two sources of data and thus obtain an
estimate of their true mass. Results. Combining radial velocity measurements
with Gaia DR3 data led to more precise mass estimations, leading us to
reclassify several systems initially labeled as brown dwarfs as low-mass stars.
Out of the 32 analyzed companions, 13 are determined to be stars, 17 are
sub-stellar, and 2 have inconclusive results with the current data.
Importantly, using these updated masses, we reevaluated the occurrence rate of
brown dwarf companions (13-80 M$_{jup}$ ) on close orbits (<10 au) in the
CORALIE sample, determining a tentative occurrence rate of
$0.8^{+0.3}_{-0.2}\%$

Earth and Planetary Astrophysics;Astrophysics of Galaxies;Solar and Stellar Astrophysics