Imaging & Spectroscopy

Early Release Science Of The Exoplanet WASP-39b With JWST NIRSpec PRISM

By Keith Cowing
Press Release
November 21, 2022
Filed under , , , , , , , , , , ,
Early Release Science Of The Exoplanet WASP-39b With JWST NIRSpec PRISM
The JWST-PRISM transmission spectrum of WASP-39b with key contributions to the atmospheric spectrum. The black points with 1-σ error bars correspond to the measured FIREFLy transit depths of the spectrophotometric light curves at different wavelengths. The best-fitting model spectrum from the PICASO 3.0 grid is shown as the grey line and the coloured regions correspond to the chemical opacity contributions at specific wavelengths. The best-fitting 1D radiative-convective thermodynamic equilibrium (RCTE) model corresponds to a super-solar metallicity and super-solar carbon-to-oxygen ratio with moderate cloud opacity (see Methods). The PRISM transmission spectrum is explained by contributions from Na (19σ), H2O (33σ), CO2 (28σ), CO (7σ), SO2 (2.7σ) and clouds (21σ). The data do not provide evidence of CH4 , H2S and K absorption (see Methods). Also, note that the detector was saturated to varying degrees between 0.8-1.9 µm. — astro-ph.EP

Transmission spectroscopy of exoplanets has revealed signatures of water vapor, aerosols, and alkali metals in a few dozen exoplanet atmospheres.

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.

Here we report a broad-wavelength 0.5-5.5 μm atmospheric transmission spectrum of WASP-39 b, a 1200 K, roughly Saturn-mass, Jupiter-radius exoplanet, measured with JWST NIRSpec’s PRISM mode as part of the JWST Transiting Exoplanet Community Early Release Science Team program. We robustly detect multiple chemical species at high significance, including Na (19σ), H2O (33σ), CO2 (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.

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

Comments: 41 pages, 4 main figures, 10 extended data figures, 4 tables. Under review in Nature
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2211.10487 [astro-ph.EP] (or arXiv:2211.10487v1 [astro-ph.EP] for this version)
Submission history
From: Zafar Rustamkulov
[v1] Fri, 18 Nov 2022 19:57:13 UTC (9,055 KB)

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