J/AJ/152/160ivo://CDS.VizieR/J/AJ/152/160doi:10.26093/cds/vizier.51520160CDSBuchhave L.A.Dressing C.D.Dumusque X.Rice K.Vanderburg A.,Mortier A.Lopez-Morales M.Lopez E.Lundkvist M.S.Kjeldsen H.,Affer L.Bonomo A.S.Charbonneau D.Collier Cameron A.Cosentino R.,Figueira P.Fiorenzano A.F.M.Harutyunyan A.Haywood R.D.Johnson J.A.,Latham D.W.Lovis C.Malavolta L.Mayor M.Micela G.Molinari E.,Motalebi F.Nascimbeni V.Pepe F.Phillips D.F.Piotto G.Pollacco D.,Queloz D.Sasselov D.Segransan D.Sozzetti A.Udry S.Watson C.2017-06-22T14:29:04Z2017-01-19T09:01:15ZCDS support team

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

cds-question@unistra.frsolar-system-planetsmultiple-starsradial-velocityKepler-20 is a solar-type star (V=12.5) hosting a compact system of five transiting planets, all packed within the orbital distance of Mercury in our own solar system. A transition from rocky to gaseous planets with a planetary transition radius of ~1.6R_{Earth}_ has recently been proposed by several articles in the literature. Kepler-20b (R_p_~1.9R_{Earth}_) has a size beyond this transition radius; however, previous mass measurements were not sufficiently precise to allow definite conclusions to be drawn regarding its composition. We present new mass measurements of three of the planets in the Kepler-20 system that are facilitated by 104 radial velocity measurements from the HARPS-N spectrograph and 30 archival Keck/HIRES observations, as well as an updated photometric analysis of the Kepler data and an asteroseismic analysis of the host star (M_*_=0.948+/-0.051M_{Sun}_ and R_*_=0.964+/-0.018R_{Sun}_). Kepler-20b is a 1.868_-0.034_^+0.066^R_{Earth}_ planet in a 3.7day period with a mass of 9.70_-1.44_^+1.41^M_{Earth}_, resulting in a mean density of 8.2_-1.3_^+1.5^g/cm^3^, indicating a rocky composition with an iron-to-silicate ratio consistent with that of the Earth. This makes Kepler-20b the most massive planet with a rocky composition found to date. Furthermore, we report the discovery of an additional non-transiting planet with a minimum mass of 19.96_-3.61_^+3.08^M_{Earth}_ and an orbital period of ~34days in the gap between Kepler-20f (P~11days) and Kepler-20d (P~78days).2016AJ....152..160Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/152/160CatalogResearchIsServedByTAP VizieR generic servicerelated-toV/133 : Kepler Input Catalog (Kepler Mission Team, 2009)J/ApJ/800/135 : HARPS-N radial velocities of KOI-69 (Dressing+, 2015)J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)J/ApJ/749/15 : The Kepler-20 planetary system (Gautier+, 2012)J/other/Nat/486.375 : Stellar parameters of KOI stars (Buchhave+, 2012)J/ApJ/736/19 : Kepler planetary candidates. II. (Borucki+, 2011)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/152/160https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/152/160http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/152/160https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/152/160https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/152/160http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/152/160GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/152/160/table1HARPS-N radial velocity measurements of Kepler-20recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Date (BJD-2400000) (1)dtime.epochdoubleRV[-20944.6/-20904.6] Radial velocitym/sphys.veloc;pos.heliocentricdoublee_RV[2.46/4.95] The 1{sigma} error in RVm/sstat.errorfloatFWHM[6843.03/6926.1] Full-Width at Half-Maximumm/sspect.line.widthfloate_FWHM[5.78/11.63] The 1{sigma} error in FWHMm/sstat.error;phys.angSizefloatlogR'HK[-5.08/-4.76] Log Ca II chromospheric activity index (Ca II log(R'_HK_))phot.flux;arith.ratiofloate_logR'HK[0.03/0.13] The 1{sigma} error in log(R'HK)stat.errorfloatS/N[23.6/41.5] Signal-to-Noise ratio at 550nmstat.snrfloat