J/AJ/156/218ivo://CDS.VizieR/J/AJ/156/218doi:10.26093/cds/vizier.51560218CDSDucrot E.Sestovic M.Morris B.M.Gillon M.Triaud A.H.M.J.De Wit J.,Thimmarayappa D.Agol E.Almleaky Y.Burdanov A.Burgasser A.J.,Delrez L.Demory B.-O.Jehin E.Leconte J.McCormac J.Murray C.,Queloz D.Selsis F.Thompson S.Van Grootel V.2020-01-17T15:39:16Z2019-04-08T13:41:25ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsphotometryspectroscopyvisible-astronomyThe TRAPPIST-1 planetary system provides an exceptional opportunity for the atmospheric characterization of temperate terrestrial exoplanets with the upcoming James Webb Space Telescope (JWST). Assessing the potential impact of stellar contamination on the planets' transit transmission spectra is an essential precursor to this characterization. Planetary transits themselves can be used to scan the stellar photosphere and to constrain its heterogeneity through transit depth variations in time and wavelength. In this context, we present our analysis of 169 transits observed in the optical from space with K2 and from the ground with the SPECULOOS and Liverpool telescopes. Combining our measured transit depths with literature results gathered in the mid-/near-IR with Spitzer/IRAC and HST/WFC3, we construct the broadband transmission spectra of the TRAPPIST-1 planets over the 0.8-4.5 {mu}m spectral range. While planet b, d, and f spectra show some structures at the 200-300 ppm level, the four others are globally flat. Even if we cannot discard their instrumental origins, two scenarios seem to be favored by the data: a stellar photosphere dominated by a few high-latitude giant (cold) spots, or, alternatively, by a few small and hot (3500-4000 K) faculae. In both cases, the stellar contamination of the transit transmission spectra is expected to be less dramatic than predicted in recent papers. Nevertheless, based on our results, stellar contamination can still be of comparable or greater order than planetary atmospheric signals at certain wavelengths. Understanding and correcting the effects of stellar heterogeneity therefore appears essential for preparing for the exploration of TRAPPIST-1 with JWST.2018AJ....156..218Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/156/218CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/156/178 : NIR transmission spectra of TRAPPIST-1 planets (Zhang+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/156/218https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/156/218http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/156/218https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/156/218https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/156/218http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/156/218GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/156/218/table1 (Number of transits observed by K2, SPECULOOS-South Observatory (SSO), and Liverpool Telescope (LT) analyzed in this work for each TRAPPIST-1 planet)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/156/218/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/156/218/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/156/218/table1?GETtext/xml+votable180.050000true346.6223333-5.04144440.0055555555555555566/18726https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/156/218?format=asciiOpticaldefaultJ/AJ/156/218/table1Number of transits observed by K2, SPECULOOS-South Observatory (SSO), and Liverpool Telescope (LT) analyzed in this work for each TRAPPIST-1 planetrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPlPlanetmeta.id;meta.maincharNK2[1/42] Number of transits observed by K2meta.numberintNSSO[2/20] Number of transits observed by the SPECULOOS-South observatorymeta.numberintNLT[1/5]? Number of transits observed by the Liverpool Telescopemeta.numberintnullableLCTransit light curvesmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/AJ/156/218/mediansMedian values and 1{sigma} limits of the posterior PDFs deduced for the timings and depths from their global analyses for SPECULOOS (table 10) , K2 (table 11) and Liverpool Telescope (table 12) observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTelTelescopemeta.id;instr.telcharPl[bcdefgh] TRAPPIST-1 planetmeta.id;meta.maincharEpoch[5/511] Epoch of the transittime.epochintTime[7738.99/8096.54] Mid-transit timing (BJD_TDB_-2450000)dtime.epochdoublee_Time[0.00012/0.01] Uncertainty in Timedstat.error;time.epochdoubleDepth[0.257/0.988] Transit depth%phys.absorption.opticalDepth;arith.ratiofloate_Depth[0.027/0.4] Uncertainty in Depth%stat.error;phys.absorption.opticalDepthfloatJ/AJ/156/218/lcDescription of the transit light curves measured for TRAPPIST-1 planets by K2 (table 3) , SPECULOOS-South (table 4) and Liverpool Telescope (table 5)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTelTelescopemeta.id;instr.telcharPl[bcdefgh] TRAPPIST-1 planetmeta.id;meta.maincharDateDate of acquisitiontime.epochnullableInstInstrument used (only in Table 4)instr.setupcharNPts[139/741] Number of data pointsmeta.numberintEpoch[5/511] Epoch based on the transit ephemeris presented in Delrez et al. (2018MNRAS.475.3577D)time.epochintBaseBaseline function (1)stat.fit.parambetaw[0.79/1.95] White noise {beta}_w_instr.det.noisefloatbetar[1/2.14] Red noise {beta}_r_instr.det.noisefloatCF[0.79/2.18] Correction factor (CF={beta}_r_*{beta}_w_)arith.factorfloatJ/AJ/156/218/timingsdepthsTransit timings and depths obtained from the individual analyses of SPECULOOS (table 6) , K2 (table 7) and Liverpool Telescope (table 8) light curvesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTelTelescopemeta.id;instr.telcharPl[bcdefgh] TRAPPIST-1 planetmeta.id;meta.maincharEpoch[5/511] Epoch of the transittime.epochintTime[7738.99/8096.54] Mid-transit timing (BJD_TDB_-2450000)dtime.epochdoublee_Time[0.00012/0.01] Uncertainty in Timedstat.error;time.epochdoubleDepth[0.257/0.988] Transit depth%phys.absorption.opticalDepth;arith.ratiofloate_Depth[0.027/0.4] Uncertainty in Depth%stat.error;phys.absorption.opticalDepthfloat