Early Release Science of the exoplanet WASP-39b with JWST NIRISS
Abstract
The Saturn-mass exoplanet WASP-39b has been the subject of extensive efforts to determine its atmospheric properties using transmission spectroscopy1-4. However, these efforts have been hampered by modelling degeneracies between composition and cloud properties that are caused by limited data quality5-9. Here, we present the transmission spectrum of WASP-39 b obtained using the SOSS mode of the NIRISS instrument on JWST. This spectrum spans 0.6–2.8 μm in wavelength and reveals multiple water absorption bands, the potassium resonance doublet, and signatures of clouds. The precision and broad wavelength coverage of NIRISS-SOSS allows us to break model degeneracies between cloud properties and the atmospheric composition of WASP-39b, favouring a heavy element enhancement (“metallicity”) of ~10–30x the solar value, a sub-solar carbon-to-oxygen (C/O) ratio, and a solar-to-super-solar potassium-to-oxygen (K/O) ratio. The observations are also best explained by wavelength-dependent, non-gray clouds with inhomogeneous coverage of the planet’s terminator.
Citation
Feinstein , A D , Radica , M , Welbanks , L , Murray , C A , Ohno , K , Coulombe , L-P , Espinoza , N , Bean , J L , Teske , J K , Benneke , B , Line , M R , Rustamkulov , Z , Saba , A , Tsiaras , A , Barstow , J K , Fortney , J J , Gao , P , Knutson , H A , MacDonald , R J , Mikal-Evans , T , Rackham , B V , Taylor , J , Parmentier , V , Batalha , N M , Berta-Thompson , Z K , Carter , A L , Changeat , Q , Dos Santos , L A , Gibson , N P , Goyal , J M , Kreidberg , L , López-Morales , M , Lothringer , J D , Miguel , Y , Molaverdikhani , K , Moran , S E , Morello , G , Mukherjee , S , Sing , D K , Stevenson , K B , Wakeford , H R , Ahrer , E-M , Alam , M K , Alderson , L , Allen , N H , Batalha , N E , Bell , T J , Blecic , J , Brande , J , Caceres , C , Casewell , S L , Chubb , K L , Crossfield , I J M , Crouzet , N , Cubillos , P E , Decin , L , Désert , J-M , Harrington , J , Heng , K , Henning , T , Iro , N , Kempton , E M -R , Kendrew , S , Kirk , J , Krick , J , Lagage , P-O , Lendl , M , Mancini , L , Mansfield , M , May , E M , Mayne , N J , Nikolov , N K , Palle , E , de la Roche , D J M P D , Piaulet , C , Powell , D , Redfield , S , Rogers , L K , Roman , M T , Roy , P-A , Nixon , M C , Schlawin , E , Tan , X , Tremblin , P , Turner , J D , Venot , O , Waalkes , W C , Wheatley , P J & Zhang , X 2023 , ' Early Release Science of the exoplanet WASP-39b with JWST NIRISS ' , Nature . https://doi.org/10.1038/s41586-022-05674-1
Publication
Nature
Status
Peer reviewed
ISSN
0028-0836Type
Journal article
Rights
Copyright © 2023 the Author(s), under exclusive licence to Springer Nature Limited. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1038/s41586-022-05674-1.
Description
Support for this program was provided by NASA through a grant from the Space Telescope Science Institute. ADF acknowledges support by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1746045. MR acknowledges support from the National Sciences and Engineering Research Council of Canada, the Fonds de Recherche du Québec, as well as the Institut de Recherche sur les Exoplanètes.Collections
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