J/A+A/622/A172ivo://CDS.VizieR/J/A+A/622/A172doi:10.26093/cds/vizier.36220172CDSMurgas F.Chen G.Palle E.Nortmann L.Nowak G.2020-01-29T09:07:36Z2019-02-21T15:34:07ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsspectroscopyRayleigh scattering in a hydrogen-dominated exoplanet atmosphere can be detected using ground- or space-based telescopes. However, stellar activity in the form of spots can mimic Rayleigh scattering in the observed transmission spectrum. Quantifying this phenomena is key to our correct interpretation of exoplanet atmospheric properties. We obtained Gran Telescopio Canarias (GTC) long-slit optical spectroscopy of two transits of HAT-P-11b with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) on August 30, 2016 and September 25, 2017. By fitting both transits together, we find a slope in the transmission spectrum showing an increase of the planetary radius towards blue wavelengths. Closer inspection of the transmission spectrum of the individual data sets reveals that the first transit presents this slope while the transmission spectrum of the second data set is flat. Additionally, we detect hints of Na absorption on the first night, but not on the second. We conclude that the transmission spectrum slope and Na absorption excess found in the first transit observation are caused by unocculted stellar spots. Modeling the contribution of unocculted spots to reproduce the results of the first night we find a spot filling factor of delta=0.62^+0.20^_-0.17_ and a spot-to-photosphere temperature difference of {Delta}T=429^+184^_-299_K.2019A&A...622A.172Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/622/A172CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/563/A41 : WASP-43 OSIRIS transmission spectroscopy (Murgas+, 2014)J/A+A/589/A62 : GTC transit light curves of CoRoT-29b (Palle+, 2016)J/A+A/594/A65 : GTC transit light curves of HAT-P-32b (Nortmann+, 2016)J/A+A/600/L11 : GTC transit light curves of WASP-52b (Chen+, 2017)J/A+A/605/A114 : GTC transit light curves of WASP-48b (Murgas+, 2017)J/A+A/616/A145 : GTC transit light curves of WASP-127b (Chen+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/622/A172https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/622/A172http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/622/A172https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/622/A172https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/622/A172http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/622/A172GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/622/A172/listList of light curve filesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRangeWavelength intervalnmem.wlcharlcShow the light curvesmeta.ref.urlcharFileNameName of the table with photometrymeta.id;phot;meta.tablecharObs.dateObservation datetime.epoch;obsnullableJ/A+A/622/A172/gtcwlcn2HAT-P-11b GTC transit white light curve (2017/09/25)FluxRelative fluxphot.flux;arith.ratiodoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Date (TDB standard)dtime.epochdoublee_FluxUncertainty of relative fluxstat.error;phot.fluxdoubleposXDrift of star on CCD in spatial directionpixpos.cartesian.x;instr.detdoubleposYDrift of star on CCD in dispersion directionpixpos.cartesian.y;instr.detdoublefwhmXRelative change of full width at half maximum of the stellar absorption line profilepixarith.rate;spect.line.widthdoublefwhmYFull width at half maximum of the stellar spatial profilepixspect.line.widthdoubleAirmAirmass during observationobs.airMassdoubleRotAngTelescope rotator angle during observationsdeginstr.offsetdoubleJ/A+A/622/A172/gtcwlcn1HAT-P-11b GTC transit white light curve (2016/08/30)FluxRelative fluxphot.flux;arith.ratiodoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Date (TDB standard)dtime.epochdoublee_FluxUncertainty of relative fluxstat.error;phot.fluxdoubleposXDrift of star on CCD in spatial directionpixpos.cartesian.x;instr.detdoubleposYDrift of star on CCD in dispersion directionpixpos.cartesian.y;instr.detdoublefwhmXRelative change of full width at half maximum of the stellar absorption line profilepixarith.rate;spect.line.widthdoublefwhmYFull width at half maximum of the stellar spatial profilepixspect.line.widthdoubleAirmAirmass during observationobs.airMassdoubleRotAngTelescope rotator angle during observationsdeginstr.offsetdouble