J/AJ/162/215ivo://CDS.VizieR/J/AJ/162/215doi:10.26093/cds/vizier.51620215CDSScarsdale N.Murphy J.M.A.Batalha N.M.Crossfield I.J.M.,Dressing C.D.Fulton B.Howard A.W.Huber D.Isaacson H.Kane S.R.,Petigura E.A.Robertson P.Roy A.Weiss L.M.Beard C.Behmard A.,Chontos A.Christiansen J.L.Ciardi D.R.Claytor Z.R.Collins K.A.,Collins K.I.Dai F.Dalba P.A.Dragomir D.Fetherolf T.Fukui A.,Giacalone S.Gonzales E.J.Hill M.L.Hirsch L.A.Jensen E.L.N.,Kosiarek M.R.De Leon J.P.Lubin J.Lund M.B.Luque R.Mayo A.W.,Mocnik T.Mori M.Narita N.Nowak G.Palle E.Rabus M.,Rosenthal L.J.Rubenzahl R.A.Schlieder J.E.Shporer A.Stassun K.G.,Twicken J.Wang G.Yahalomi D.A.Jenkins J.Latham D.W.Ricker G.R.,Seager S.Vanderspek R.Winn J.N.2025-05-05T20:07:37Z2022-01-27T07:53:24ZCDS support team

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

cds-question@unistra.frexoplanetsg-starsradial-velocityvisible-astronomyWe present the discovery of two nearly identically sized sub-Neptune transiting planets orbiting HD63935, a bright (V=8.6mag), Sun-like (Teff=5560K) star at 49pc. TESS identified the first planet, HD63935b (TOI-509.01), in Sectors 7 and 34. We identified the second signal (HD63935c) in Keck High Resolution Echelle Spectrometer and Lick Automated Planet Finder radial velocity data as part of our follow-up campaign. It was subsequently confirmed with TESS photometry in Sector 34 as TOI-509.02. Our analysis of the photometric and radial velocity data yielded a robust detection of both planets with periods of 9.0600{+/-}0.007 and 21.40{+/-}0.0019days, radii of 2.99{+/-}0.14 and 2.90{+/-}0.13R{Earth}, and masses of 10.8{+/-}1.8 and 11.1{+/-}2.4M{Earth}. We calculated densities for planets b and c consistent with a few percent of the planet mass in hydrogen/helium envelopes. We also describe our survey's efforts to choose the best targets for James Webb Space Telescope atmospheric follow-up. These efforts suggest that HD 63935 b has the most clearly visible atmosphere of its class. It is the best target for transmission spectroscopy (ranked by the transmission spectroscopy metric, a proxy for atmospheric observability) in the so far uncharacterized parameter space comprising sub-Neptune-sized (2.6R{Earth}<Rp<4R{Earth}), moderately irradiated (100F{Earth}<Fp<1000F{Earth}) planets around G stars. Planet c is also a viable target for transmission spectroscopy, and given the indistinguishable masses and radii of the two planets, the system serves as a natural laboratory for examining the processes that shape the evolution of sub-Neptune planets.2021AJ....162..215Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/162/215CatalogResearchIsServedByTAP VizieR generic servicerelated-toI/337 : Gaia DR1 (Gaia Collaboration, 2016)I/345 : Gaia DR2 (Gaia Collaboration, 2018)J/other/Nat/486.375 : Stellar parameters of KOI stars (Buchhave+, 2012)J/ApJ/776/67 : Rotational tracks (van Saders+, 2013)J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)J/A+A/564/A125 : AGN Torus model comparison of AGN in the CDFS (Buchner+, 2014)J/A+A/580/A23 : Stroemgren-Crawford uvby{beta} photometry cat (Paunzen, 2015)J/AJ/152/180 : Bolometric fluxes of eclipsing bin in Tycho-2 (Stassun+, 2016)J/ApJ/825/19 : Mass-radius relationship planets with Rp<4 (Wolfgang+, 2016)J/ApJS/226/7 : Planet cands discovered using K2's 1st yr (Crossfield+, 2016)J/AJ/153/71 : Kepler follow-up obs program. I. Imaging (Furlan+, 2017)J/AJ/153/136 : Planets & their host stars Gaia parallaxes (Stassun+, 2017)J/AJ/154/107 : California-Kepler Survey. I. 1305 stars (Petigura+, 2017)J/AJ/154/109 : California-Kepler Survey. III. Planet radii (Fulton+, 2017)J/ApJ/834/17 : Mass & radius of planets, moons, low mass stars (Chen+, 2017)J/ApJ/844/102 : KIC star plxs from asteroseismology vs Gaia (Huber+, 2017)J/A+A/619/L10 : pi Men radial velocity curves (Gandolfi+, 2018)J/AJ/155/48 : California-Kepler Survey. V. Masses and radii (Weiss+, 2018)J/ApJS/235/38 : Kepler planetary cand. VIII. DR25 reliability (Thompson+, 2018)J/ApJS/244/11 : Planet candidates and EBs in K2 campaigns 0-8 (Kruse+, 2019)J/AJ/159/241 : TESS-Keck Survey. I. HD332231 Radial Velocities (Dalba+, 2020)J/AJ/159/280 : Gaia-Kepler stellar properties cat.I. KIC stars (Berger+, 2020)J/ApJ/888/43 : APOGEE-Kepler Cool Dwarf star ages (Claytor+, 2020)J/AJ/161/56 : The TESS-Keck Survey. II. RVs of TOI-561 (Weiss+, 2021)J/AJ/161/70 : RVel for WASP-107 with HIRES & CORALIE (Piaulet+, 2021)J/AJ/161/119 : The TESS-Keck survey. IV. Rvel for WASP-107 (Rubenzahl+, 2021)J/ApJS/254/39 : Exoplanet candidates from TESS first 2yr obs (Guerrero+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/162/215https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/162/215http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/162/215https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/162/215https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/162/215http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/162/215GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/162/215/table2Radial velocitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[2458576/2459281] Barycentric Julian Date; TBDdtime.epochdoubleTelTelescope and/or instrument identifier (1)meta.id;instrcharRVel[-172/26.6] Relative radial velocitym/sphys.veloc;pos.heliocentricfloate_RVel[0.5/19] Uncertainty in RVelm/sstat.error;spect.dopplerVelocfloatS-Value[0.02/0.38]? MtWilson CaHK S activity indic. (2)meta.codefloatnullablee_S-Value[0.001/0.004]? Uncertainty in S-Valuestat.errorfloatnullable