Radial velocity follow-up of astrometric substellar companions: 6 confirmed brown dwarfs and 13 impostor binaries Gaia
Year: 2026
Type: article
Abstract: With microarcsecond precision, has made the astrometric discovery of substellar companions feasible. However, follow-up observations are needed to verify orbital solutions and rule out astrophysical false positives. We validate and characterise a sample of 20 Data Release 3 (DR3) astrometric candidates for substellar companions, with the dual goal of identifying false positives and deriving robust physical parameters for genuine companions. We performed high-resolution spectroscopy using FIES, NIRPS, and NEID at the Nordic Optical Telescope, the ESO 3.6m telescope, and the WIYN Telescope, respectively. Double-lined spectroscopic binaries were identified as false positives, and surviving systems were characterised through joint astrometry and radial velocity modelling. Thirteen of the candidates proved to be near-twin binary stars for which the astrometric motion of the centre of light is small enough to mimic that of a single star in response to a substellar companion. We confirm that six companions are brown dwarfs with masses in the range ∼26--68,M_ candidates, we find that the astrometric orbital solutions are generally reliable to within the stated uncertainties. Gaia Gaia Gaia two of them for the first time. In contrast to earlier studies of lower-mass Gaia
Source: Astronomy and Astrophysics
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Funders: National Science Foundation, National Aeronautics and Space Administration, Princeton University, University of Wisconsin-Madison, Aarhus Universitet, Pennsylvania State University, NASA Exoplanet Science Institute, European Space Agency, European Southern Observatory, Universitetet i Oslo, Háskóli Íslands, Turun Yliopisto, Stockholms Universitet, Instituto de Astrofísica de Canarias
OpenAlex ID: W7223313365