Powell, Diana;
Feinstein, Adina D;
Lee, Elspeth KH;
Zhang, Michael;
Tsai, Shang-Min;
Taylor, Jake;
Kirk, James;
... Yurchenko, Sergei N; + view all
(2024)
Sulfur dioxide in the mid-infrared transmission spectrum of WASP-39b.
Nature
, 626
pp. 797-783.
10.1038/s41586-024-07040-9.
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Abstract
The recent inference of sulphur dioxide (SO₂) in the atmosphere of the hot (1100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations (1–3) suggests that photochemistry is a key process in high temperature exoplanet atmospheres (4). This is due to the low (<1 ppb) abundance of SO₂ under thermochemical equilibrium, compared to 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 findings (4). In addition to 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 ∼7.1–8.0 × solar and demonstrate that photochemistry shapes the spectra of WASP-39b across a broad wavelength range.
| Type: | Article |
|---|---|
| Title: | Sulfur dioxide in the mid-infrared transmission spectrum of WASP-39b |
| Location: | England |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1038/s41586-024-07040-9 |
| Publisher version: | https://doi.org/10.1038/s41586-024-07040-9 |
| Language: | English |
| Additional information: | This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. |
| Keywords: | Atmospheric chemistry, Exoplanets |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10185907 |
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