J/AJ/155/173ivo://CDS.VizieR/J/AJ/155/173doi:10.26093/cds/vizier.51550173CDSCurtis J.L.Vanderburg A.Torres G.Kraus A.L.Huber D.Mann A.W.,Rizzuto A.C.Isaacson H.Howard A.W.Henze C.E.Fulton B.J.,Wright J.T.2020-08-31T13:59:30Z2020-05-06T13:01:48ZCDS support team

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

cds-question@unistra.frphotometryvisible-astronomyexoplanetsWe identify a sub-Neptune exoplanet (R_p_=2.5+/-0.2R_{Earth}_) transiting a solar twin in the Ruprecht 147 star cluster (3Gyr, 300pc, [Fe/H]=+0.1dex). The ~81 day light curve for EPIC 219800881 (V=12.71) from K2 Campaign 7 shows six transits with a period of 13.84 days, a depth of ~0.06%, and a duration of ~4hr. Based on our analysis of high-resolution MIKE spectra, broadband optical and NIR photometry, the cluster parallax and interstellar reddening, and isochrone models from PARSEC, Dartmouth, and MIST, we estimate the following properties for the host star: M_*_=1.01+/-0.03M_{sun}_, R_*_=0.95+/-0.03R_{sun}_, and T_eff_=5695+/-50K. This star appears to be single based on our modeling of the photometry, the low radial velocity (RV) variability measured over nearly 10yr, and Keck/NIRC2 adaptive optics imaging and aperture-masking interferometry. Applying a probabilistic mass-radius relation, we estimate that the mass of this planet is M_p_=7+5-3M_{Earth}_, which would cause an RV semi-amplitude of K=2+/-1m/s that may be measurable with existing precise RV facilities. After statistically validating this planet with BLENDER, we now designate it K2-231b, making it the second substellar object to be discovered in Ruprecht 147 and the first planet; it joins the small but growing ranks of 22 other planets and three candidates found in open clusters.2018AJ....155..173Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/155/173CatalogResearchIsServedByTAP VizieR generic servicerelated-toII/336 : AAVSO Photometric All Sky Survey (APASS) DR9 (Henden+, 2016)I/339 : Hot Stuff for One Year (HSOY) (Altmann+, 2017)IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)J/ApJS/152/261 : Ca II emission in nearby stars (Wright+, 2004)J/ApJS/159/141 : Spectroscopic properties of cool stars. I. (Valenti+, 2005)J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 2010)J/ApJS/190/1 : A survey of stellar families (Raghavan+, 2010)J/ApJ/725/331 : Astrometry in the Galactic Center (Yelda+, 2010)J/ApJ/725/875 : Chromospheric activity for CPS stars (Isaacson+, 2010)J/ApJ/731/8 : Multiple star formation in Taurus-Auriga (Kraus+, 2011)J/A+A/529/A75 : Limb-darkening coefficients (Claret+, 2011)J/ApJ/733/L9 : Stellar rotation for 71 NGC 6811 members (Meibom+, 2011)J/ApJ/756/L33 : RVs of 2 hot Jupiters in Praesepe (Quinn+, 2012)J/ApJ/764/78 : Oxygen abundances in nearby FGK stars (Ramirez+, 2013)J/AJ/145/134 : RVs of 108 stars in Ruprecht 147 (Curtis+, 2013)J/ApJS/208/9 : Intrinsic colors & temp. of PMS stars (Pecaut+, 2013)J/ApJS/210/20 : Small Kepler planets radial velocities (Marcy+, 2014)J/A+A/564/A125 : AGN Torus model comparison of AGN in CDFS (Buchner+, 2014)J/AJ/150/97 : RVs in M67. I. 1278 candidate members (Geller+, 2015)J/ApJS/222/14 : Planetary cand. from 1st yr K2 mission (Vanderburg+, 2016)J/A+A/588/A118 : Pr0211 RVs, photom. & activity indexes (Malavolta+, 2016)J/ApJS/224/2 : K2 EPIC stellar data for 138600 targets (Huber+, 2016)J/AJ/152/8 : Stellar mult. impact on planetary syst. I. (Kraus+, 2016)J/ApJ/825/19 : Mass-radius relationship for planets (Wolfgang+, 2016)J/ApJS/225/32 : Extended abundance analysis of cool stars (Brewer+, 2016)J/A+A/594/A100 : K2 new planetary and EB candidates (Barros+, 2016)J/MNRAS/463/1780 : Exoplanet candidates in Praesepe (M 44) (Libralato+, 2016)J/MNRAS/463/1831 : M67 Kepler/K2 variable stars (Nardiello+, 2016)J/ApJ/834/17 : Mass+rad. of planets, moons, low mass stars (Chen+, 2017)J/ApJ/835/25 : Calibrated solar S-index time series (Egeland+, 2017)J/A+A/603/A85 : M67 stars radial velocities (Brucalassi+, 2017)J/ApJ/844/102 : KIC star plx from asteroseismology vs Gaia (Huber+, 2017)J/AJ/154/109 : California-Kepler Survey (CKS). III. Radii (Fulton+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/155/173https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/155/173http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/155/173https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/155/173https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/155/173http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/155/173GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/155/173/fig1K2 light curve for EPIC 219800881 (Data behind Figure 1)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDObservation date, BJD-2454833dtime.epochdoubleFlux-Norm[0.98/1.02] Normalized flux (1)phot.flux;arith.ratiodoubleFlux-Detr[0.99/1.01] Detrended flux (2)phot.flux;arith.ratiodouble