Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM

Rustamkulov, Z; Sing, D K; Mukherjee, S; May, E M; Kirk, J; Schlawin, E; Line, M R; Piaulet, C; Carter, A L; Batalha, N E; Goyal, J M; López-Morales, M; Lothringer, J D; MacDonald, R J; Moran, S E; Stevenson, K B; Wakeford, H R; Espinoza, N; Bean, J L; Batalha, N M; Benneke, B; Berta-Thompson, Z K; Crossfield, I J M; Gao, P; Kreidberg, L; Powell, D K; Cubillos, P E; Gibson, N P; Leconte, J; Molaverdikhani, K; Nikolov, N K; Parmentier, V; Roy, P; Taylor, J; Turner, J D; Wheatley, P J; Aggarwal, K; Ahrer, E; Alam, M K; Alderson, L; Allen, N H; Banerjee, A; Barat, S; Barrado, D; Barstow, J K; Bell, T J; Blecic, J; Brande, J; Casewell, S; Changeat, Q; Chubb, K L; Crouzet, N; Daylan, T; Decin, L; Désert, J; Mikal-Evans, T; Feinstein, A D; Flagg, L; Fortney, J J; Harrington, J; Heng, K; Hong, Y; Hu, R; Iro, N; Kataria, T; Kempton, E M-R; Krick, J; Lendl, M; Lillo-Box, J; Louca, A; Lustig-Yaeger, J; Mancini, L; Mansfield, M; Mayne, N J; Miguel, Y; Morello, G; Ohno, K; Palle, E; Petit Dit de la Roche, D J M; Rackham, B V; Radica, M; Ramos-Rosado, L; Redfield, S; Rogers, L K; Shkolnik, E L; Southworth, J; Teske, J; Tremblin, P; Tucker, G S; Venot, O; Waalkes, W C; Welbanks, L; Zhang, X and Zieba, S (2023). Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM. Nature, 614(7949) pp. 659–663.

DOI: https://doi.org/10.1038/s41586-022-05677-y

Abstract

Transmission spectroscopy^1,2,3 of exoplanets has revealed signatures of water vapor, aerosols, and alkali metals in a few dozen exoplanet atmospheres^4,5 . However, these previous inferences with the Hubble and Spitzer Space Telescopes were hindered by the observations' relatively narrow wavelength range and spectral resolving power, which precluded the unambiguous identification of other chemical species - in particular the primary carbon-bearing molecules^6,7 . Here we report a broad-wavelength 0.5-5.5 µm atmospheric transmission spectrum of WASP39 b⁸, a 1200 K, roughly Saturn-mass, Jupiter-radius exoplanet, measured with JWST NIRSpec's PRISM mode⁹ as part of the JWST Transiting Exoplanet Community Early Release Science Team program^10,11,12 . We robustly detect multiple chemical species at high significance, including Na (19σ), H O (33σ), CO (28σ), and CO (7σ). The non-detection of CH₄ , combined with a strong CO₂ feature, favours atmospheric models with a super-solar atmospheric metallicity. An unanticipated absorption feature at 4µm is best explained by SO₂ (2.7σ), which could be a tracer of atmospheric photochemistry. These observations demonstrate JWST's sensitivity to a rich diversity of exoplanet compositions and chemical processes.