J/AJ/169/107ivo://CDS.VizieR/J/AJ/169/107doi:10.26093/cds/vizier/be-59-3bCDSStefansson G.Mahadevan S.Winn J.N.Marcussen M.L.Kanodia S.,Albrecht S.Fitzmaurice E.Mikulskyte O.Canas C.I.,Espinoza-Retamal J.I.Zwart Y.Krolikowski D.M.Hotnisky A.,Robertson P.Alvarado-Montes J.A.Bender C.F.Blake C.H.,Callingham J.R.Cochran W.D.Delamer M.Diddams S.A.Dong J.,Fernandes R.B.Giovinazzi M.R.Halverson S.Libby-Roberts J.,Logsdon S.E.McElwain M.W.Ninan J.P.Rajagopal J.Reji V.Roy A.,Schwab C.Wright J.T.2026-07-02T11:45:16Z2025-12-04T13:16:12ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frradial-velocityexoplanetsm-starsproper-motionsspectroscopyvisible-astronomyGaia astrometry of nearby stars is precise enough to detect the tiny displacements induced by substellar companions, but radial velocity (RV) data are needed for definitive confirmation. Here we present RV follow-up observations of 28 M and K stars with candidate astrometric substellar companions, which led to the confirmation of two systems, Gaia-4b and Gaia-5b, identification of five systems that are single lined but require additional data to confirm as substellar companions, and the refutation of 21 systems as stellar binaries. Gaia-4b is a massive planet (M=11.8+/-0.7M_J_) in a P=571.3+/-1.4d orbit with a projected semimajor axis a0=0.312+/-0.040mas orbiting a 0.644+/-0.02M_{sun}_ star. Gaia-5b is a brown dwarf (M=20.9+/-0.5M_J_) in a P=358.62+/-0.20d eccentric e=0.6423+/-0.0026 orbit with a projected angular semimajor axis of a0=0.947+/-0.038mas around a 0.34+/-0.03M_{sun}_ star. Gaia-4b is one of the first exoplanets discovered via the astrometric technique, and is one of the most massive planets known to orbit a low-mass star.2025AJ....169..107Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/169/107CatalogResearchIsServedByTAP VizieR generic servicerelated-toII/328 : AllWISE Data Release (Cutri+ 2013)IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)I/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)J/ApJ/622/1102 : The planet-metallicity correlation. (Fischer+, 2005)J/A+A/525/A95 : Search for brown-dwarf companions of stars (Sahlmann+, 2011)J/A+A/547/A105 : D-burning in core accretion objects (Molliere+, 2012)J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)J/ApJ/828/46 : ALMA survey of Lupus protoplanetary disks. I. (Ansdell+, 2016)J/ApJ/831/125 : ALMA 887um obs. of ChaI star-forming region (Pascucci+, 2016)J/A+A/603/A30 : Evidence for 2 distinct giant planet population (Santos+, 2017)J/AJ/156/102 : The TESS Input Catalog & Candidate Target List (Stassun+, 2018)J/A+A/624/A94 : The role of the host star's metallicity (Maldonado+, 2019)J/other/Sci/365.1441 : GJ 3512 radial velocity & light curves (Morales+, 2019)J/ApJ/892/31 : Teff and metallicities of M dwarfs in APOGEE DR14 (Birky+, 2020)J/MNRAS/491/5216 : Rotation per. for 107 M dwarfs from APACHE (Giacobbe+, 2020)J/AJ/159/100 : Flux & RVs of the dwarf G9-40 with K2 & HPF (Stefansson+, 2020)J/AJ/160/192 : Photometry and RVs of K2-25b with HPF (Stefansson+, 2020)J/A+A/649/A6 : Gaia Catalogue of Nearby Stars - GCNS (Gaia collaboration, 2021)J/A+A/664/A65 : Early-M dwarfs occurrence rates (Pinamonti+, 2022)J/A+A/663/A48 : Two Saturn-mass planets around M dwarfs (Quirrenbach+, 2022)J/A+A/674/A114 : Southern extrasolar planets CORALIE surv. XIX (Barbato+, 2023)J/A+A/674/A10 : Gaia DR3 systems with companions (Holl+, 2023)J/AJ/165/120 : g and i'-band light curve of TOI-5205 with SDSS (Kanodia+, 2023)J/AJ/166/11 : Stellar properties & RV variability for M-dwarfs (Pass+, 2023)J/other/Sci/382.1031 : LHS 3154 RV and activity indicators (Stefansson+, 2023)J/A+A/680/A16 : RV measurements for 12 stars (Unger+, 2023)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/169/107https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/169/107http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/169/107https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/169/107https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/169/107http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/169/107GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/169/107/table5Radial velocities of Gaia-4recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[2460039/2460562] Barycentric Julian Date at TDBdtime.epochdoubleRVel[-393/222] Radial velocitym/sspect.dopplerVelocfloate_RVel[5.8/26.4] Uncertainty in RVelm/sstat.error;spect.dopplerVelocfloatInstInstrument used for RVel (1)meta.id;instrcharJ/AJ/169/107/table6Radial velocities of Gaia-5recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[2460069/2460600] Barycentric Julian date at TDBdtime.epochdoubleRVel[-1692/1176] Radial velocitym/sspect.dopplerVelocfloate_RVel[10.5/39.1] Uncertainty in RVelm/sstat.error;spect.dopplerVelocfloatInstInstrument used for RVel (1)meta.id;instrchar