J/AJ/169/109ivo://CDS.VizieR/J/AJ/169/109doi:10.26093/cds/vizier/be-59-3dCDSTyler D.Petigura E.A.Rogers J.Lubin J.Seifhart A.Bean J.L.,Brady M.Luque R.2026-07-02T11:45:17Z2025-12-04T14:29:22ZCDS support team

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

cds-question@unistra.frexoplanetsradial-velocitym-starsdwarf-starsspectroscopyvisible-astronomyWe present an analysis of 126 new radial velocity measurements from the MAROON-X spectrograph to investigate the TOI-1266 system, which hosts two known transiting sub-Neptunes at 10.8 and 18.8 days. We integrated our measurements with existing HARPS-N measurements for this system and derived revised masses for TOI-1266 b and c of M_b_=4.09+/-0.45M_{Earth}_ and M_c_=2.64+/-0.52M_{Earth}_, respectively. The Keplerian fit from the combined datasets enabled an ~35% and ~41% improvement in mass precision for planet b and c, respectively, compared to the previously published values. With bulk densities of {rho}_b_=1.25+/-0.21g/cm3 and {rho}_c_=1.51+/-0.39g/cm, the planets are among the lowest density sub-Neptunes orbiting an M dwarf. They are both consistent with rocky cores surrounded by hydrogen helium envelopes. TOI-1266 c may also be consistent with a water-rich composition, but we disfavor that interpretation from an Occam's razor perspective.2025AJ....169..109Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/169/109CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/MNRAS/422/2024 : X-ray-age relation & exoplanet evaporation (Jackson+, 2012)J/ApJ/807/45 : Potentially habitable planets orbit. M dwarfs (Dressing+, 2015)J/AJ/154/109 : California-Kepler Surv. (CKS). III. Planet radii (Fulton+, 2017)J/AJ/159/211 : Exoplanets parameters from Kepler and K2 (Cloutier+, 2020)J/MNRAS/491/5287 : Exoplanet evaporation in multitransiting syst. (Owen+, 2020)J/AJ/160/259 : HPF RVs and TESS photometry of TOI-1266 (Stefansson+, 2020)J/AJ/161/36 : 117 exoplanets in habitable zone with Kepler DR25 (Bryson+, 2021)J/AJ/162/55 : 65 Transit-timing variation planets properties (Yee+, 2021)J/other/Sci/377.1211 : RV and LC of 8 M dwarf stars with planets (Luque+, 2022)J/AJ/163/179 : The California-Kepler Survey. X. (Petigura+, 2022)J/AJ/163/168 : Photometry and radial velocity of LTT 1445A (Winters+, 2022)J/AJ/165/167 : HARPS-N radial velocities of TOI-1695 (Cherubim+, 2023)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/169/109https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/169/109http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/169/109https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/169/109https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/169/109http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/169/109GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/169/109/fig2MAROON-X radial velocities of TOI-1266 (data behind Figure 2)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[2459660/2460140] Barycentric Julian Datedtime.epochdoubleRVel[-7.32/7.52] Radial velocitym/sspect.dopplerVelocfloate_RVel[0.64/2.8] Uncertainty in RVelm/sstat.error;spect.dopplerVelocfloatArmSpectrograph arm identifier (1)meta.id;instrchar