J/AJ/161/70ivo://CDS.VizieR/J/AJ/161/70doi:10.26093/cds/vizier.51610070CDSPiaulet C.Benneke B.Rubenzahl R.A.Howard A.W.Lee E.J.Thorngren D.,Angus R.Peterson M.Schlieder J.E.Werner M.Kreidberg L.Jaouni T.,Crossfield I.J.M.Ciardi D.R.Petigura E.A.Livingston J.Dressing C.D.,Fulton B.J.Beichman C.Christiansen J.L.Gorjian V.Hardegree-Ullman K.K.Krick J.Sinukoff E.2022-09-30T21:39:35Z2021-04-16T09:05:13ZCDS support team

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

cds-question@unistra.frexoplanetsk-starsradial-velocityvisible-astronomyspectroscopyWith a mass in the Neptune regime and a radius of Jupiter, WASP-107b presents a challenge to planet formation theories. Meanwhile, the planet's low surface gravity and the star's brightness also make it one of the most favorable targets for atmospheric characterization. Here, we present the results of an extensive 4yr Keck/HIRES radial-velocity (RV) follow-up program of the WASP-107 system and provide a detailed study of the physics governing the accretion of the gas envelope of WASP-107b. We reveal that WASP-107b's mass is only 1.8 Neptune masses (Mb=30.5{+/-}1.7M{Earth}). The resulting extraordinarily low density suggests that WASP-107b has a H/He envelope mass fraction of >85% unless it is substantially inflated. The corresponding core mass of <4.6M{Earth} at 3{sigma} is significantly lower than what is traditionally assumed to be necessary to trigger massive gas envelope accretion. We demonstrate that this large gas-to-core mass ratio most plausibly results from the onset of accretion at >~1 au onto a low-opacity, dust-free atmosphere and subsequent migration to the present-day ab=0.0566{+/-}0.0017au. Beyond WASP-107b, we also detect a second, more massive planet (M_c_sini=0.36{+/-}0.04M_J_) on a wide eccentric orbit (ec=0.28{+/-}0.07) that may have influenced the orbital migration and spin-orbit misalignment of WASP-107b. Overall, our new RV observations and envelope accretion modeling provide crucial insights into the intriguing nature of WASP-107b and the system's formation history. Looking ahead, WASP-107b will be a keystone planet to understand the physics of gas envelope accretion.2021AJ....161...70Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/161/70CatalogResearchIsServedByTAP VizieR generic servicerelated-toI/259 : The Tycho-2 Catalogue (Hog+ 2000)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)I/345 : Gaia DR2 (Gaia Collaboration, 2018)J/A+A/575/A36 : BAGEMASS code (Maxted+, 2015)J/ApJ/831/64 : Mass-metallicity relation for giant planets (Thorngren+, 2016)J/ApJ/844/102 : KIC star parallaxes from asteroseismology vs Gaia (Huber+,2017)J/AJ/153/215 : Photometry and spectroscopy of KELT-11 (Pepper+, 2017)J/AJ/153/142 : Radial velocities systems hosting sub-Saturns (Petigura+, 2017)J/ApJ/836/77 : A library of high-S/N optical spectra of FGKM stars (Yee+,2017)J/ApJ/862/33 : Improved & expanded member. catalog for NGC752 (Agueros+, 2018)J/AJ/155/165 : Dissipation in exoplanet hosts from tidal spin-up (Penev+,2018)J/AJ/155/255 : Radial velocity & activity measurements of HAT-P-11 (Yee+,2018)J/A+A/621/A49 : K2-18 HARPS time-series (Cloutier+, 2019)J/ApJ/879/49 : Rotation periods for 171 Gaia members of NGC6811 (Curtis+,2019)J/ApJ/874/L31 : Giant planet bulk & atmosphere metallicities (Thorngren+,2019)J/AJ/160/90 : Stellar parameters for 13196 Kepler dwarfs (Angus+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/161/70https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/161/70http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/161/70https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/161/70https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/161/70http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/161/70GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/161/70/table1Radial velocity and activity measurementsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[2455651/2459042] Barycentric Julian Date; TDBdtime.epochdoubleRVel[-29.01/37.27] Barycentric radial velocitym/sphys.veloc;pos.heliocentricfloate_RVel[1.43/13.05] Uncertainty in RVelm/sstat.error;phys.velocfloatSHK[0.66/1.23]? S_HK_ indexspect.indexfloatnullablee_SHK[0.001]? Uncertainty in SHKstat.errorfloatnullableTel[1/2] Instrument flag (1)meta.code.error;instrint