The tale of the three planets: 3D cloud feedback increases the spectral diversity of warm Jupiters

November 2026 • 2026A&A...715A..67M

Authors • Mehta, Nishil • Parmentier, Vivien • Tan, Xianyu • Lee, Elspeth K. H. • Guillot, Tristan • Murphy, Matthew M. • Greene, Thomas P. • Beatty, Thomas G. • Bell, Taylor J. • Fortney, Jonathan J. • Line, Michael R. • Mukherjee, Sagnick • Ohno, Kazumasa • Schlawin, Everett • Triantafillides, Anastasia • Welbanks, Luis • Wiser, Lindsey S.

Abstract • Context. The JWST has revealed a large diversity of warm Jupiter spectra, despite broadly similar planetary parameters across the population. The main driver of this diversity remains unclear. Aims. We aim to identify the mechanisms responsible for the spectral differences of three warm Jupiter-size exoplanets observed by JWST: whereas WASP-80b appears mostly cloud-free, both WASP-107b and WASP-69b have spectra dominated by clouds. Methods. We modeled each planet using the same framework, ADAM (formerly SPARC/MITgcm), which solves for the interactions among cloud transport, radiative transfer, and atmospheric circulation in 3D. We investigated three condensate species (Na₂S, KCl, and MgSiO₃) and four particle sizes (0.1, 1, 5, and 10 µm). Results. Clouds settle deeper in the atmosphere of the higher-gravity planet WASP-80b than in WASP-107b, and the model reproduces their spectral difference naturally. For WASP-107b, three cloud models can reproduce the NIRCam observations: 5 µm Na₂S, 1 µm KCl, and 5 µm MgSiO₃. However, they cannot match the scattering slope observed at shorter wavelengths in NIRISS or the possible silicate feature in the MIRI bandpass, suggesting a multimodal cloud distribution. Our model predicts that small silicate particles are homogeneously distributed and thus cannot account for the difference between the two limb spectra in the MIRI bandpass. Finally, applying the same model to WASP-69b does not yield a partially cloudy dayside solution that fits the emission spectra, as proposed in a previous study. Conclusions. Coupling among 3D circulation, clouds, and radiative transfer can increase the spectral diversity of warm Jupiter exoplanets, particularly through changes in cloudiness with gravity. The combination of multiphase, wide-wavelength coverage and models that couple clouds, circulation, and radiative transfer is key to advancing our understanding of these new objects.

Links

• POSTSCRIPT https://www.aanda.org/10.1051/0004-6361/202660698/postscript
• PREPRINT http://arxiv.org/abs/2604.26911