J/MNRAS/497/5182ivo://CDS.VizieR/J/MNRAS/497/5182doi:10.26093/cds/vizier.74975182CDSAlderson L.Kirk J.Lopez-Morales M.Wheatley P.J.Skillen I.,Henry G.W.McGruder C.Brogi M.Louden T.King G.2024-08-21T20:15:46Z2020-09-07T13:28:41ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsvisible-astronomyspectroscopyWe present the optical transmission spectrum of the highly inflated Saturn- mass exoplanet WASP-21b, using three transits obtained with the ACAM instrument on the William Herschel Telescope through the LRG-BEASTS survey (Low Resolution Ground-Based Exoplanet Atmosphere Survey using Transmission Spectroscopy). Our transmission spectrum covers a wavelength range of 4635-9000{AA}, achieving an average transit depth precision of 197ppm compared to one atmospheric scale height at 246ppm. We detect NaI absorption in a bin width of 30{AA}, at >4{sigma} confidence, which extends over 100{AA}. We see no evidence of absorption from KI. Atmospheric retrieval analysis of the scattering slope indicates it is too steep for Rayleigh scattering from H_2, but is very similar to that of HD 189733b. The features observed in our transmission spectrum cannot be caused by stellar activity alone, with photometric monitoring of WASP-21 showing it to be an inactive star. We therefore conclude that aerosols in the atmosphere of WASP-21b are giving rise to the steep slope that we observe, and that WASP-21b is an excellent target for infra-red observations to constrain its atmospheric metallicity.2020MNRAS.497.5182Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/497/5182CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/519/A98 : Transit of exoplanet WASP-21b (Bouchy+, 2010)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/497/5182https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/497/5182http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/497/5182https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/497/5182https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/497/5182http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/497/5182GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/MNRAS/497/5182/wlc-n1Reduced white light curve from night 1 with timerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRowRow numbermeta.id;meta.mainintMJDModified Julian Datedtime.epochdoubleFluxNormalised white light fluxphot.flux;arith.ratiodoublee_FluxNormalised white light errorstat.error;phot.fluxdoubleJ/MNRAS/497/5182/wlc-n2Reduced white light curve from night 2 with time and FWHMrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRowRow numbermeta.id;meta.mainintMJDModified Julian Datedtime.epochdoubleFWHMFull width half maximumspect.line.widthdoubleFluxNormalised white light fluxphot.flux;arith.ratiodoublee_FluxNormalised white light errorstat.error;phot.fluxdoubleJ/MNRAS/497/5182/wlc-n3Reduced white light curve from night 3 with time and FWHMrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRowRow numbermeta.id;meta.mainintMJDModified Julian Datedtime.epochdoubleFWHMFull width half maximumspect.line.widthdoubleFluxNormalised white light fluxphot.flux;arith.ratiodoublee_FluxNormalised white light errorstat.error;phot.fluxdoubleJ/MNRAS/497/5182/slc-n1Reduced binned light curve from night 1 with timerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRowRow numbermeta.id;meta.mainintMJDModified Julian Datedtime.epochdoubleFlux1Normalised flux in 270{AA}-wide bin centred on 4635{AA}phot.flux;arith.ratiodoublee_Flux1Normalised error in 270{AA}-wide bin centred on 4635{AA}stat.errordoubleFlux2Normalised flux in 180{AA}-wide bin centred on 4860{AA}phot.flux;arith.ratiodoublee_Flux2Normalised error in 180{AA}-wide bin centred on 4860{AA}stat.errordoubleFlux3Normalised flux in 280{AA}-wide bin centred on 5090{AA}phot.flux;arith.ratiodoublee_Flux3Normalised error in 280{AA}-wide bin centred on 5090{AA}stat.errordoubleFlux4Normalised flux in 250{AA}-wide bin centred on 5355{AA}phot.flux;arith.ratiodoublee_Flux4Normalised error in 250{AA}-wide bin centred on 5355{AA}stat.errordoubleFlux5Normalised flux in 218{AA}-wide bin centred on 5589{AA}phot.flux;arith.ratiodoublee_Flux5Normalised error in 218{AA}-wide bin centred on 5589{AA}stat.errordoubleFlux6Normalised flux in 70{AA}-wide bin centred on 5733{AA}phot.flux;arith.ratiodoublee_Flux6Normalised error in 70{AA}-wide bin centred on 5733{AA}stat.errordoubleFlux7Normalised flux in 60{AA}-wide bin centred on 5798{AA}phot.flux;arith.ratiodoublee_Flux7Normalised error in 60{AA}-wide bin centred on 5798{AA}stat.errordoubleFlux8Normalised flux in 50{AA}-wide bin centred on 5853{AA}phot.flux;arith.ratiodoublee_Flux8Normalised error in 50{AA}-wide bin centred on 5853{AA}stat.errordoubleFlux9Normalised flux in 30{AA}-wide bin centred on 5893{AA}phot.flux;arith.ratiodoublee_Flux9Normalised error in 30{AA}-wide bin centred on 5893{AA}stat.errordoubleFlux10Normalised flux in 50{AA}-wide bin centred on 5933{AA}phot.flux;arith.ratiodoublee_Flux10Normalised error in 50{AA}-wide bin centred on 5933{AA}stat.errordoubleFlux11Normalised flux in 60{AA}-wide bin centred on 5988{AA}phot.flux;arith.ratiodoublee_Flux11Normalised error in 60{AA}-wide bin centred on 5988{AA}stat.errordoubleFlux12Normalised flux in 70{AA}-wide bin centred on 6053{AA}phot.flux;arith.ratiodoublee_Flux12Normalised error in 70{AA}-wide bin centred on 6053{AA}stat.errordoubleFlux13Normalised flux in 142{AA}-wide bin centred on 6159{AA}phot.flux;arith.ratiodoublee_Flux13Normalised error in 142{AA}-wide bin centred on 6159{AA}stat.errordoubleFlux14Normalised flux in 200{AA}-wide bin centred on 6330{AA}phot.flux;arith.ratiodoublee_Flux14Normalised error in 200{AA}-wide bin centred on 6330{AA}stat.errordoubleFlux15Normalised flux in 300{AA}-wide bin centred on 6580{AA}phot.flux;arith.ratiodoublee_Flux15Normalised error in 300{AA}-wide bin centred on 6580{AA}stat.errordoubleFlux16Normalised flux in 250{AA}-wide bin centred on 6855{AA}phot.flux;arith.ratiodoublee_Flux16Normalised error in 250{AA}-wide bin centred on 6855{AA}stat.errordoubleFlux17Normalised flux in 135{AA}-wide bin centred on 7047{AA}phot.flux;arith.ratiodoublee_Flux17Normalised error in 135{AA}-wide bin centred on 7047{AA}stat.errordoubleFlux18Normalised flux in 255{AA}-wide bin centred on 7242{AA}phot.flux;arith.ratiodoublee_Flux18Normalised error in 255{AA}-wide bin centred on 7242{AA}stat.errordoubleFlux19Normalised flux in 150{AA}-wide bin centred on 7445{AA}phot.flux;arith.ratiodoublee_Flux19Normalised error in 150{AA}-wide bin centred on 7445{AA}stat.errordoubleFlux20Normalised flux in 350{AA}-wide bin centred on 7695{AA}phot.flux;arith.ratiodoublee_Flux20Normalised error in 350{AA}-wide bin centred on 7695{AA}stat.errordoubleFlux21Normalised flux in 200{AA}-wide bin centred on 7970{AA}phot.flux;arith.ratiodoublee_Flux21Normalised error in 200{AA}-wide bin centred on 7970{AA}stat.errordoubleFlux22Normalised flux in 300{AA}-wide bin centred on 8220{AA}phot.flux;arith.ratiodoublee_Flux22Normalised error in 300{AA}-wide bin centred on 8220{AA}stat.errordoubleFlux23Normalised flux in 230{AA}-wide bin centred on 8485{AA}phot.flux;arith.ratiodoublee_Flux23Normalised error in 230{AA}-wide bin centred on 8485{AA}stat.errordoubleFlux24Normalised flux in 200{AA}-wide bin centred on 8700{AA}phot.flux;arith.ratiodoublee_Flux24Normalised error in 200{AA}-wide bin centred on 8700{AA}stat.errordoubleFlux25Normalised flux in 400{AA}-wide bin centred on 9000{AA}phot.flux;arith.ratiodoublee_Flux25Normalised error in 400{AA}-wide bin centred on 9000{AA}stat.errordoubleJ/MNRAS/497/5182/slc-n2Reduced binned light curve from night 2 with time and FWHMRowRow numbermeta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian Datedtime.epochdoubleFWHMFull width half maximumspect.line.widthdoubleFlux1Normalised flux in 270{AA}-wide bin centred on 4635{AA}phot.flux;arith.ratiodoublee_Flux1Normalised error in 270{AA}-wide bin centred on 4635{AA}stat.errordoubleFlux2Normalised flux in 180{AA}-wide bin centred on 4860{AA}phot.flux;arith.ratiodoublee_Flux2Normalised error in 180{AA}-wide bin centred on 4860{AA}stat.errordoubleFlux3Normalised flux in 280{AA}-wide bin centred on 5090{AA}phot.flux;arith.ratiodoublee_Flux3Normalised error in 280{AA}-wide bin centred on 5090{AA}stat.errordoubleFlux4Normalised flux in 250{AA}-wide bin centred on 5355{AA}phot.flux;arith.ratiodoublee_Flux4Normalised error in 250{AA}-wide bin centred on 5355{AA}stat.errordoubleFlux5Normalised flux in 218{AA}-wide bin centred on 5589{AA}phot.flux;arith.ratiodoublee_Flux5Normalised error in 218{AA}-wide bin centred on 5589{AA}stat.errordoubleFlux6Normalised flux in 70{AA}-wide bin centred on 5733{AA}phot.flux;arith.ratiodoublee_Flux6Normalised error in 70{AA}-wide bin centred on 5733{AA}stat.errordoubleFlux7Normalised flux in 60{AA}-wide bin centred on 5798{AA}phot.flux;arith.ratiodoublee_Flux7Normalised error in 60{AA}-wide bin centred on 5798{AA}stat.errordoubleFlux8Normalised flux in 50{AA}-wide bin centred on 5853{AA}phot.flux;arith.ratiodoublee_Flux8Normalised error in 50{AA}-wide bin centred on 5853{AA}stat.errordoubleFlux9Normalised flux in 30{AA}-wide bin centred on 5893{AA}phot.flux;arith.ratiodoublee_Flux9Normalised error in 30{AA}-wide bin centred on 5893{AA}stat.errordoubleFlux10Normalised flux in 50{AA}-wide bin centred on 5933{AA}phot.flux;arith.ratiodoublee_Flux10Normalised error in 50{AA}-wide bin centred on 5933{AA}stat.errordoubleFlux11Normalised flux in 60{AA}-wide bin centred on 5988{AA}phot.flux;arith.ratiodoublee_Flux11Normalised error in 60{AA}-wide bin centred on 5988{AA}stat.errordoubleFlux12Normalised flux in 70{AA}-wide bin centred on 6053{AA}phot.flux;arith.ratiodoublee_Flux12Normalised error in 70{AA}-wide bin centred on 6053{AA}stat.errordoubleFlux13Normalised flux in 142{AA}-wide bin centred on 6159{AA}phot.flux;arith.ratiodoublee_Flux13Normalised error in 142{AA}-wide bin centred on 6159{AA}stat.errordoubleFlux14Normalised flux in 200{AA}-wide bin centred on 6330{AA}phot.flux;arith.ratiodoublee_Flux14Normalised error in 200{AA}-wide bin centred on 6330{AA}stat.errordoubleFlux15Normalised error in 300{AA}-wide bin centred on 6580{AA}phot.flux;arith.ratiodoublee_Flux15Normalised flux in 300{AA}-wide bin centred on 6580{AA}stat.errordoubleFlux16Normalised flux in 250{AA}-wide bin centred on 6855{AA}phot.flux;arith.ratiodoublee_Flux16Normalised error in 250{AA}-wide bin centred on 6855{AA}stat.errordoubleFlux17Normalised flux in 135{AA}-wide bin centred on 7047{AA}phot.flux;arith.ratiodoublee_Flux17Normalised error in 135{AA}-wide bin centred on 7047{AA}stat.errordoubleFlux18Normalised flux in 255{AA}-wide bin centred on 7242{AA}phot.flux;arith.ratiodoublee_Flux18Normalised error in 255{AA}-wide bin centred on 7242{AA}stat.errordoubleFlux19Normalised flux in 150{AA}-wide bin centred on 7445{AA}phot.flux;arith.ratiodoublee_Flux19Normalised error in 150{AA}-wide bin centred on 7445{AA}stat.errordoubleFlux20Normalised flux in 350{AA}-wide bin centred on 7695{AA}phot.flux;arith.ratiodoublee_Flux20Normalised error in 350{AA}-wide bin centred on 7695{AA}stat.errordoubleFlux21Normalised flux in 200{AA}-wide bin centred on 7970{AA}phot.flux;arith.ratiodoublee_Flux21Normalised error in 200{AA}-wide bin centred on 7970{AA}stat.errordoubleFlux22Normalised flux in 300{AA}-wide bin centred on 8220{AA}phot.flux;arith.ratiodoublee_Flux22Normalised error in 300{AA}-wide bin centred on 8220{AA}stat.errordoubleFlux23Normalised flux in 230{AA}-wide bin centred on 8485{AA}phot.flux;arith.ratiodoublee_Flux23Normalised error in 230{AA}-wide bin centred on 8485{AA}stat.errordoubleFlux24Normalised flux in 200{AA}-wide bin centred on 8700{AA}phot.flux;arith.ratiodoublee_Flux24Normalised error in 200{AA}-wide bin centred on 8700{AA}stat.errordoubleFlux25Normalised flux in 400{AA}-wide bin centred on 9000{AA}phot.flux;arith.ratiodoublee_Flux25Normalised error in 400{AA}-wide bin centred on 9000{AA}stat.errordoubleJ/MNRAS/497/5182/slc-n3Reduced binned light curve from night 3 with FWHM and sky backgroundRowRow numbermeta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian Datedtime.epochdoubleFWHMFull width half maximumspect.line.widthdoubleSky1Sky background in 270{AA}-wide bin centred on 4635{AA}phot.mag.sbdoubleFlux1Normalised flux in 270{AA}-wide bin centred on 4635{AA}phot.flux;arith.ratiodoublee_Flux1Normalised error in 270{AA}-wide bin centred on 4635{AA}stat.errordoubleSky2Sky background in 180{AA}-wide bin centred on 4860{AA}phot.mag.sbdoubleFlux2Normalised flux in 180{AA}-wide bin centred on 4860{AA}phot.flux;arith.ratiodoublee_Flux2Normalised error in 180{AA}-wide bin centred on 4860{AA}stat.errordoubleSky3Sky background in 280{AA}-wide bin centred on 5090{AA}phot.mag.sbdoubleFlux3Normalised flux in 280{AA}-wide bin centred on 5090{AA}phot.flux;arith.ratiodoublee_Flux3Normalised error in 280{AA}-wide bin centred on 5090{AA}stat.errordoubleSky4Sky background in 250{AA}-wide bin centred on 5355{AA}phot.mag.sbdoubleFlux4Normalised flux in 250{AA}-wide bin centred on 5355{AA}phot.flux;arith.ratiodoublee_Flux4Normalised error in 250{AA}-wide bin centred on 5355{AA}stat.errordoubleSky5Sky background in 218{AA}-wide bin centred on 5589{AA}phot.mag.sbdoubleFlux5Normalised flux in 218{AA}-wide bin centred on 5589{AA}phot.flux;arith.ratiodoublee_Flux5Normalised error in 218{AA}-wide bin centred on 5589{AA}stat.errordoubleSky6Sky background in 70{AA}-wide bin centred on 5733{AA}phot.mag.sbdoubleFlux6Normalised flux in 70{AA}-wide bin centred on 5733{AA}phot.flux;arith.ratiodoublee_Flux6Normalised error in 70{AA}-wide bin centred on 5733{AA}stat.errordoubleSky7Sky background in 60{AA}-wide bin centred on 5798{AA}phot.mag.sbdoubleFlux7Normalised flux in 60{AA}-wide bin centred on 5798{AA}phot.flux;arith.ratiodoublee_Flux7Normalised error in 60{AA}-wide bin centred on 5798{AA}stat.errordoubleSky8Sky background in 50{AA}-wide bin centred on 5853{AA}phot.mag.sbdoubleFlux8Normalised flux in 50{AA}-wide bin centred on 5853{AA}phot.flux;arith.ratiodoublee_Flux8Normalised error in 50{AA}-wide bin centred on 5853{AA}stat.errordoubleSky9Sky background in 30{AA}-wide bin centred on 5893{AA}phot.mag.sbdoubleFlux9Normalised flux in 30{AA}-wide bin centred on 5893{AA}phot.flux;arith.ratiodoublee_Flux9Normalised error in 30{AA}-wide bin centred on 5893{AA}stat.errordoubleSky10Sky background in 50{AA}-wide bin centred on 5933{AA}phot.mag.sbdoubleFlux10Normalised flux in 50{AA}-wide bin centred on 5933{AA}phot.flux;arith.ratiodoublee_Flux10Normalised error in 50{AA}-wide bin centred on 5933{AA}stat.errordoubleSky11Sky background in 60{AA}-wide bin centred on 5988{AA}phot.mag.sbdoubleFlux11Normalised flux in 60{AA}-wide bin centred on 5988{AA}phot.flux;arith.ratiodoublee_Flux11Normalised error in 60{AA}-wide bin centred on 5988{AA}stat.errordoubleSky12Sky background in 70{AA}-wide bin centred on 6053{AA}phot.mag.sbdoubleFlux12Normalised flux in 70{AA}-wide bin centred on 6053{AA}phot.flux;arith.ratiodoublee_Flux12Normalised error in 70{AA}-wide bin centred on 6053{AA}stat.errordoubleSky13Sky background in 142{AA}-wide bin centred on 6159{AA}phot.mag.sbdoubleFlux13Normalised flux in 142{AA}-wide bin centred on 6159{AA}phot.flux;arith.ratiodoublee_Flux13Normalised error in 142{AA}-wide bin centred on 6159{AA}stat.errordoubleSky14Sky background in 200{AA}-wide bin centred on 6330{AA}phot.mag.sbdoubleFlux14Normalised flux in 200{AA}-wide bin centred on 6330{AA}phot.flux;arith.ratiodoublee_Flux14Normalised error in 200{AA}-wide bin centred on 6330{AA}stat.errordoubleSky15Sky background in 300{AA}-wide bin centred on 6580{AA}phot.mag.sbdoubleFlux15Normalised flux in 300{AA}-wide bin centred on 6580{AA}phot.flux;arith.ratiodoublee_Flux15Normalised error in 300{AA}-wide bin centred on 6580{AA}stat.errordoubleSky16Sky background in 250{AA}-wide bin centred on 6855{AA}phot.mag.sbdoubleFlux16Normalised flux in 250{AA}-wide bin centred on 6855{AA}phot.flux;arith.ratiodoublee_Flux16Normalised error in 250{AA}-wide bin centred on 6855{AA}stat.errordoubleSky17Sky background in 135{AA}-wide bin centred on 7047{AA}phot.mag.sbdoubleFlux17Normalised flux in 135{AA}-wide bin centred on 7047{AA}phot.flux;arith.ratiodoublee_Flux17Normalised error in 135{AA}-wide bin centred on 7047{AA}stat.errordoubleSky18Sky background in 255{AA}-wide bin centred on 7242{AA}phot.mag.sbdoubleFlux18Normalised flux in 255{AA}-wide bin centred on 7242{AA}phot.flux;arith.ratiodoublee_Flux18Normalised error in 255{AA}-wide bin centred on 7242{AA}stat.errordoubleSky19Sky background in 150{AA}-wide bin centred on 7445{AA}phot.mag.sbdoubleFlux19Normalised flux in 150{AA}-wide bin centred on 7445{AA}phot.flux;arith.ratiodoublee_Flux19Normalised error in 150{AA}-wide bin centred on 7445{AA}stat.errordoubleSky20Sky background in 350{AA}-wide bin centred on 7695{AA}phot.mag.sbdoubleFlux20Normalised flux in 350{AA}-wide bin centred on 7695{AA}phot.flux;arith.ratiodoublee_Flux20Normalised error in 350{AA}-wide bin centred on 7695{AA}stat.errordoubleSky21Sky background in 200{AA}-wide bin centred on 7970{AA}phot.mag.sbdoubleFlux21Normalised flux in 200{AA}-wide bin centred on 7970{AA}phot.flux;arith.ratiodoublee_Flux21Normalised error in 200{AA}-wide bin centred on 7970{AA}stat.errordoubleSky22Sky background in 300{AA}-wide bin centred on 8220{AA}phot.mag.sbdoubleFlux22Normalised flux in 300{AA}-wide bin centred on 8220{AA}phot.flux;arith.ratiodoublee_Flux22Normalised error in 300{AA}-wide bin centred on 8220{AA}stat.errordoubleSky23Sky background in 230{AA}-wide bin centred on 8485{AA}phot.mag.sbdoubleFlux23Normalised flux in 230{AA}-wide bin centred on 8485{AA}phot.flux;arith.ratiodoublee_Flux23Normalised error in 230{AA}-wide bin centred on 8485{AA}stat.errordoubleSky24Sky background in 200{AA}-wide bin centred on 8700{AA}phot.mag.sbdoubleFlux24Normalised flux in 200{AA}-wide bin centred on 8700{AA}phot.flux;arith.ratiodoublee_Flux24Normalised error in 200{AA}-wide bin centred on 8700{AA}stat.errordoubleSky25Sky background in 400{AA}-wide bin centred on 9000{AA}phot.mag.sbdoubleFlux25Normalised flux in 400{AA}-wide bin centred on 9000{AA}phot.flux;arith.ratiodoublee_Flux25Normalised error in 400{AA}-wide bin centred on 9000{AA}stat.errordouble