J/ApJ/747/35ivo://CDS.VizieR/J/ApJ/747/35doi:10.26093/cds/vizier.17470035CDSBerta Z.K.Charbonneau D.Desert J.-M.Miller-Ricci Kempton E.,McCullough P.R.Burke C.J.Fortney J.J.Irwin J.Nutzman P.Homeier D.2017-06-27T06:38:45Z2013-10-24T10:01:25ZCDS support team

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

cds-question@unistra.frsolar-system-planetsmultiple-starsspectrophotometryCapitalizing on the observational advantage offered by its tiny M dwarf host, we present Hubble Space Telescope/Wide Field Camera 3 (WFC3) grism measurements of the transmission spectrum of the super-Earth exoplanet GJ1214b. These are the first published WFC3 observations of a transiting exoplanet atmosphere. After correcting for a ramp-like instrumental systematic, we achieve nearly photon-limited precision in these observations, finding the transmission spectrum of GJ1214b to be flat between 1.1 and 1.7{mu}m. Inconsistent with a cloud-free solar composition atmosphere at 8.2{sigma}, the measured achromatic transit depth most likely implies a large mean molecular weight for GJ1214b's outer envelope. A dense atmosphere rules out bulk compositions for GJ1214b that explain its large radius by the presence of a very low density gas layer surrounding the planet. High-altitude clouds can alternatively explain the flat transmission spectrum, but they would need to be optically thick up to 10 mbar or consist of particles with a range of sizes approaching 1 {mu}m in diameter.2012ApJ...747...35Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/747/35CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)J/A+A/549/A10 : Transits of GJ 1214 (Harpsoe+, 2013)J/A+A/538/A46 : Transit observations of GJ1214b (de Mooij+, 2012)J/ApJ/731/123 : APOSTLE light curve of GJ 1214b (Kundurthy+, 2011)J/ApJ/736/12 : Transit light curves of GJ1214 (Berta+, 2011)J/ApJ/716/1336 : Stability analysis of single-planet (Kopparapu+, 2010)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/747/35https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/747/35http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/747/35https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/747/35https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/747/35http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/747/35GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJ/747/35/table1White light curves from WFC3/G141Visit[1/3] Visit numbermeta.id;obsintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Date at mid-exposuredtime.epochdoubleRFlux[0.98/1.01] Relative flux (1)phot.flux;arith.ratiodoublee_RFluxUncertainty in RFluxstat.errordoubleSkySky background in electrons/sct/sinstr.backgroundfloatX0The 0th order X position (2)pixpos.cartesian.x;instr.detdoubleY0The 0th order Y position (2)pixpos.cartesian.y;instr.detfloatA0Gaussian width of 0th order spectrum in the horizontal directionpixstat.variance;spect.line.widthfloatB0Gaussian width of 0th order spectrum in the vertical directionpixstat.variance;spect.line.widthfloatY1The 1st order Y position (2)pixpos.cartesian.y;instr.detfloatB1Gaussian width of 1st order spectrum in the vertical directionpixstat.variance;spect.line.widthfloatSlopeSlope of 1st order spectrumarith.graddouble