Sulfur dioxide in the mid-infrared transmission spectrum of WASP-39b
Journal article, 2024
The recent inference of sulfur dioxide (SO2) in the atmosphere of the hot (approximately 1,100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations1–3 suggests that photochemistry is a key process in high-temperature exoplanet atmospheres4. This is because of the low (<1 ppb) abundance of SO2 under thermochemical equilibrium compared with that produced from the photochemistry of H2O and H2S (1–10 ppm)4–9. However, the SO2 inference was made from a single, small molecular feature in the transmission spectrum of WASP-39b at 4.05 μm and, therefore, the detection of other SO2 absorption bands at different wavelengths is needed to better constrain the SO2 abundance. Here we report the detection of SO2 spectral features at 7.7 and 8.5 μm in the 5–12-μm transmission spectrum of WASP-39b measured by the JWST Mid-Infrared Instrument (MIRI) Low Resolution Spectrometer (LRS)10. Our observations suggest an abundance of SO2 of 0.5–25 ppm (1σ range), consistent with previous findings4. As well as SO2, we find broad water-vapour absorption features, as well as an unexplained decrease in the transit depth at wavelengths longer than 10 μm. Fitting the spectrum with a grid of atmospheric forward models, we derive an atmospheric heavy-element content (metallicity) for WASP-39b of approximately 7.1–8.0 times solar and demonstrate that photochemistry shapes the spectra of WASP-39b across a broad wavelength range.
Light
Photochemistry
Sulfur Dioxide
Extraterrestrial Environment
Atmosphere
Author
Diana Powell
Harvard-Smithsonian Center for Astrophysics
University of Chicago
A. D. Feinstein
University of Colorado at Boulder
University of Chicago
Elspeth K.H. Lee
University of Bern
Michael Zhang
University of Chicago
Shang Min Tsai
University of California
Jake Taylor
Université de Montréal
University of Oxford
J. Kirk
Imperial College London
Taylor Bell
NASA Ames Research Center
J. Barstow
Open University
Peter Gao
Carnegie Institution of Washington
Jacob L. Bean
University of Chicago
Jasmina Blecic
New York University Abu Dhabi
Katy L. Chubb
University of St Andrews
I. J.M. Crossfield
University of Kansas
Sean Jordan
University of Cambridge
D. Kitzmann
University of Colorado at Boulder
Sarah E. Moran
University of Arizona
Giuseppe Morello
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Istituto nazionale di astrofisica (INAF)
Instituto de Astrofísica de Canarias
Julianne I. Moses
Space Science Institute
Luis Welbanks
Arizona State University
Jeehyun Yang
California Institute of Technology (Caltech)
Xi Zhang
University of California
Eva Maria Ahrer
The University of Warwick
Aaron Bello-Arufe
California Institute of Technology (Caltech)
Jonathan Brande
University of Kansas
Sarah Casewell
University Of Leicester
N. Crouzet
Leiden University
P. E. Cubillos
Istituto nazionale di astrofisica (INAF)
Institut fur Weltraumforschung
B.O. Demory
University of Bern
Physics Institute
A. Dyrek
University Paris-Saclay
Laura Flagg
Cornell University
Renyu Hu
California Institute of Technology (Caltech)
Julie Inglis
California Institute of Technology (Caltech)
K. Jones
University of Bern
L. Kreidberg
Max Planck Society
Mercedes López-Morales
Harvard-Smithsonian Center for Astrophysics
P. O. Lagage
University Paris-Saclay
E. Meier Valdes
University of Bern
Yamila Miguel
Leiden University
Netherlands Institute for Space Research (SRON)
Vivien Parmentier
Observatoire de la Cote d'Azur
Anjali A.A. Piette
Carnegie Institution of Washington
Benjamin V. Rackham
Massachusetts Institute of Technology (MIT)
Michael Radica
Université de Montréal
S. Redfield
Wesleyan University
Kevin B. Stevenson
The Johns Hopkins University Applied Physics Laboratory
Hannah R. Wakeford
University of Bristol
Keshav Aggarwal
Indian Institute of Technology Indore
Munazza K. Alam
Carnegie Institution of Washington
Natalie Batalha
University of California
Natasha E. Batalha
NASA Ames Research Center
B. Benneke
Université de Montréal
Zach K. Berta-Thompson
University of Colorado at Boulder
Ryan P. Brady
University College London (UCL)
Claudio Caceres
Núcleo Milenio de Formación Planetaria (NPF)
Centro de Astrofísica y Tecnologías Afines (CATA),
Universidad Andrés Bello
Aarynn L. Carter
University of California
J. M. Desert
Anton Pannekoek Institute for Astronomy
Joseph Harrington
University of Central Florida
Nicolas Iro
German Aerospace Center (DLR)
Michael R. Line
Arizona State University
Joshua D. Lothringer
Utah Valley University
Ryan J. MacDonald
University of Michigan
Luigi Mancini
Istituto nazionale di astrofisica (INAF)
Max Planck Society
University of Rome Tor Vergata
K. Molaverdikhani
Ludwig Maximilian University of Munich (LMU)
Sagnick Mukherjee
University of California
M. C. Nixon
University of Maryland
A. V. Oza
California Institute of Technology (Caltech)
Enric Palle
Instituto de Astrofísica de Canarias
Zafar Rustamkulov
Johns Hopkins University
David K. Sing
Johns Hopkins University
Maria E. Steinrueck
Max Planck Society
Olivia Venot
Paris Descartes University
P. J. Wheatley
The University of Warwick
Sergey N. Yurchenko
University College London (UCL)
Nature
0028-0836 (ISSN) 1476-4687 (eISSN)
Vol. 626 8001 979-983Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
DOI
10.1038/s41586-024-07040-9
PubMed
38232945