J/AJ/160/230ivo://CDS.VizieR/J/AJ/160/230doi:10.26093/cds/vizier.51600230CDSMcGruder C.D.Lopez-Morales M.Espinoza N.Rackham B.V.Apai D.,Jordan A.Osip D.J.Alam M.K.Bixel A.Fortney J.J.Henry G.W.,Kirk J.Lewis N.K.Rodler F.Weaver I.C.2021-12-08T18:46:42Z2021-02-08T12:58:43ZCDS support team

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

cds-question@unistra.frexoplanetsstellar-radiivisible-astronomyspectroscopyWe present a new optical (400-950nm) transmission spectrum of the hot Jupiter WASP-31b (M=0.48M_Jup_; R=1.54R_Jup_; P=3.41days), obtained by combining four transit observations. These transits were observed with IMACS on the Magellan Baade Telescope at Las Campanas Observatory as part of the ACCESS project. We investigate the presence of clouds/hazes in the upper atmosphere of this planet, as well as the contribution of stellar activity on the observed features. In addition, we search for absorption features of the alkali elements NaI and KI, with particular focus on KI, for which there have been two previously published disagreeing results. Observations with Hubble Space Telescope (HST)/STIS detected KI, whereas ground-based low- and high- resolution observations did not. We use equilibrium and nonequilibrium chemistry retrievals to explore the planetary and stellar parameter space of the system with our optical data combined with existing near-IR observations. Our best-fit model is that with a scattering slope consistent with a Rayleigh slope ({alpha}=5.3_-3.1_^+2.9^), high-altitude clouds at a log cloud top pressure of -3.6_-2.1_^+2.7^bars, and possible muted H2O features. We find that our observations support other ground-based claims of no KI. Clouds are likely why signals like H2O are extremely muted and Na or K cannot be detected. We then juxtapose our Magellan/IMACS transmission spectrum with existing VLT/FORS2, HST/WFC3, HST/STIS, and Spitzer observations to further constrain the optical-to-infrared atmospheric features of the planet. We find that a steeper scattering slope ({alpha}=8.3{+/-}1.5) is anchored by STIS wavelengths blueward of 400nm and only the original STIS observations show significant potassium signal.2020AJ....160..230Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/160/230CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/531/A60 : WASP-31b photometry and radial velocities (Anderson+, 2011)J/ApJ/736/12 : Transit light curves of GJ1214 (Berta+, 2011)J/MNRAS/419/2233 : HD 80606 transits (Colon+, 2012)J/A+A/564/A125 : AGN Torus model comparison of AGN in CDFS (Buchner+, 2014)J/ApJ/791/55 : HD 189733b in transit light curve (McCullough+, 2014)J/MNRAS/446/2428 : WASP-31b:HST/Spitzer transmission spectra (Sing+, 2015)J/AJ/152/204 : HARPS-N radial velocities of HD 179070 (Lopez-Morales+,2016)J/AJ/153/191 : Transiting planet GJ 1132 (Southworth+, 2017)J/A+A/616/A145 : GTC transit light curves of WASP-127b (Chen+, 2018)J/A+A/614/A35 : Differential photometry of GJ1214 (Mallonn+, 2018)J/A+A/624/A62 : HAT-P-32b differential photometry time serie (Mallonn+,2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/160/230https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/160/230http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/160/230https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/160/230https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/160/230http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/160/230GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/160/230/table2Observing Log for WASP-31b Data Sets from Magellan/IMACSBinBinninginstr.paramcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObs[2013/2019] Observation yeartime.epochObs.T-bTime of observation, begintime.epochnullableObs.T-eTime of observation, endtime.epochnullableAirMmin[1.02] Minimum airmassobs.airMassfloatAirMmax[1.3/1.5] Maximum airmassobs.airMassfloatTexp[27/60] Exposure timestime.duration;obs.exposureintTexpmax[36]? Maximum exposurer timestime.expointnullableRead[26/31] Readout timestime.epochintFrames[168/363] Framesinstr.paramintCamCamerainstr.paramcharRmin[295/739] Minimum resolutionspect.resolutionintRmax[822/1233] Maximum resolutionspect.resolutionintJ/AJ/160/230/table6Magellan/IMACS optical transmission spectrum (planet radius/star radius,p) for each of our four transit epochsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdamin[401/847] Lower bound of wavelength range for given binnminstr.bandwidthfloatlambdamax[416/964] Upper bound of wavelength range for given binnminstr.bandwidthfloatRpRs1[0.11/0.17]? Radius of planet of Radius of star for transit UT130226 (1)phys.size;arith.ratiofloatnullableE_RpRs1[0.002/0.02]? Upper bound of 1-sigma RpRs uncertainty for transit UT130226stat.error;stat.maxfloatnullablee_RpRs1[-0.009/-0.002]? Lower bound of 1-sigma RpRs uncertainty for transit UT130226stat.errorfloatnullableRpRs2[0.12/0.14]? Radius of planet of Radius over star for transit UT130425 (1)phys.size;arith.ratiofloatnullableE_RpRs2[0.001/0.005]? Upper bound of 1-sigma RpRs uncertainty for transit UT130425stat.error;stat.maxfloatnullablee_RpRs2[-0.005/-0.001]? Lower bound of 1-sigma RpRs uncertainty for transit UT130425stat.errorfloatnullableRpRs3[0.12/0.14]? Radius of planet of Radius over star for transit UT140222 (1)phys.size;arith.ratiofloatnullableE_RpRs3[0.001/0.007]? Upper bound of 1-sigma RpRs uncertainty for transit UT140222stat.error;stat.maxfloatnullablee_RpRs3[-0.008/-0.001]? Lower bound of 1-sigma RpRs uncertainty for transit UT140222stat.errorfloatnullableRpRs4[0.11/0.14]? Radius of planet of Radius over star for transit UT190314 (1)phys.size;arith.ratiofloatnullableE_RpRs4[0.001/0.008]? Upper bound of 1-sigma RpRs uncertainty for transit UT190314stat.error;stat.maxfloatnullablee_RpRs4[-0.02/-0.001]? Lower bound of 1-sigma RpRs uncertainty for transit UT190314stat.errorfloatnullableJ/AJ/160/230/table7Combined transmission spectrum (planet radius/star radius) for each of our four transit epochsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdamin[401/847] Upper bound of wavelength range for given binnminstr.bandwidthfloatlambdamax[416/964] Lower bound of wavelength range for given binnminstr.bandwidthfloatlambda[409/899] Mean wavelength for given binnmem.wl;stat.meanfloatRpRs[0.12/0.14] Radius of planet over Radius of star for combined spectra (1)phys.size;arith.ratiofloatRpRsminMinimum value for RpRsphys.size;arith.ratiofloatRpRsmaxMaximum value for RpRsphys.size;arith.ratiofloat