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SO 2 , silicate clouds, but no CH 4 detected in a warm Neptune.
- Source :
-
Nature [Nature] 2024 Jan; Vol. 625 (7993), pp. 51-54. Date of Electronic Publication: 2023 Nov 15. - Publication Year :
- 2024
-
Abstract
- WASP-107b is a warm (approximately 740 K) transiting planet with a Neptune-like mass of roughly 30.5 M <subscript>⊕</subscript> and Jupiter-like radius of about 0.94 R <subscript>J</subscript> (refs. <superscript>1,2</superscript> ), whose extended atmosphere is eroding <superscript>3</superscript> . Previous observations showed evidence for water vapour and a thick, high-altitude condensate layer in the atmosphere of WASP-107b (refs. <superscript>4,5</superscript> ). Recently, photochemically produced sulfur dioxide (SO <subscript>2</subscript> ) was detected in the atmosphere of a hot (about 1,200 K) Saturn-mass planet from transmission spectroscopy near 4.05 μm (refs. <superscript>6,7</superscript> ), but for temperatures below about 1,000 K, sulfur is predicted to preferably form sulfur allotropes instead of SO <subscript>2</subscript> (refs. <superscript>8-10</superscript> ). Here we report the 9σ detection of two fundamental vibration bands of SO <subscript>2</subscript> , at 7.35 μm and 8.69 μm, in the transmission spectrum of WASP-107b using the Mid-Infrared Instrument (MIRI) of JWST. This discovery establishes WASP-107b as the second irradiated exoplanet with confirmed photochemistry, extending the temperature range of exoplanets exhibiting detected photochemistry from about 1,200 K down to about 740 K. Furthermore, our spectral analysis reveals the presence of silicate clouds, which are strongly favoured (around 7σ) over simpler cloud set-ups. Furthermore, water is detected (around 12σ) but methane is not. These findings provide evidence of disequilibrium chemistry and indicate a dynamically active atmosphere with a super-solar metallicity.<br /> (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)
- Subjects :
- Planets
Silicates
Sulfur
Neptune
Extraterrestrial Environment
Subjects
Details
- Language :
- English
- ISSN :
- 1476-4687
- Volume :
- 625
- Issue :
- 7993
- Database :
- MEDLINE
- Journal :
- Nature
- Publication Type :
- Academic Journal
- Accession number :
- 37967578
- Full Text :
- https://doi.org/10.1038/s41586-023-06849-0