Early Release Science of the exoplanetWASP-39b with JWST NIRISS
Feinstein, AD; Radica, M; Welbanks, L; et al.Murray, CA; Ohno, K; Coulombe, L-P; Espinoza, N; Bean, JL; Benneke, B; Line, MR; Rustamkulov, Z; Saba, A; Tsiaris, A; Barstow, JK; Fortney, JJ; Gao, P; Knutson, HA; MacDonald, RJ; Mikal-Evans, T; Rackham, BV; Taylor, J; Parmentier, V; Batalha, NE; Berta-Thompson, ZK; Carter, AL; Changeat, Q; Dos Santos, LA; Gibson, NP; Goyal, JM; Kreidberg, L; López-Morales, M; Lothringer, JD; Migue, Y; Molaverdikhani, K; Moran, SE; Morello, G; Mukherjee, S; Sing, DK; Stevenson, KB; Wakeford, HR; Ahrer, E-M; Alam, MK; Alderson, L; Allen, NH; Batalha, NM; Bell, TJ; Blecic, J; Brande, J; Caceres, C; Casewell, SL; Chubb, KL; Crossfield, IJM; Crouzet, N; Cubillos, PE; Decin, L; Désert, J-M; Harrington, J; Heng, K; Henning, T; Iro, N; Kempton, EM-R; Kendrew, S; Kirk, J; Krick, J; Lagage, P-O; Lendl, M; Mancini, L; Mansfield, M; May, EM; Mayne, NJ; Nikolov, NK; Palle, E; Petit dit de la Roche, DJM; Piaulet, C; Powell, D; Redfield, S; Rogers, LK; Roman, MT; Roy, P-A; Nixon, MC; Schlawin, E; Tan, X; Tremblin, P; Turner, JD; Venot, O; Waalkes, WC; Wheatley, PJ; Zhang, X
Date: 9 January 2023
Article
Journal
Nature
Publisher
Nature Research
Publisher DOI
Abstract
The Saturn-mass exoplanet WASP-39b has been the subject of extensive efforts to determine its atmospheric properties using transmission spectroscopy. However, these efforts have been hampered by modelling degeneracies between composition and cloud properties that are caused by limited data quality. Here, we present the transmission ...
The Saturn-mass exoplanet WASP-39b has been the subject of extensive efforts to determine its atmospheric properties using transmission spectroscopy. However, these efforts have been hampered by modelling degeneracies between composition and cloud properties that are caused by limited data quality. Here, we present the transmission spectrum of WASP-39 b obtained using the SOSS mode of the NIRISS instrument on JWST. This spectrum spans 0.6–2.8𝝻m 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.
Physics and Astronomy
Faculty of Environment, Science and Economy
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