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arXiv · 2507.18861

Silicate clouds and a circumplanetary disk in the YSES-1 exoplanet system

Kielan K. W. Hoch·Melanie Rowland·Simon Petrus·Evert Nasedkin·Carl Ingebretsen·Jens Kammerer·Marshall Perrin·Valentina D'Orazi·William O. Balmer·Travis Barman·Mickael Bonnefoy·Gael Chauvin·Christine Chen·Rob J. De Rosa·Julien Girard·Eileen Gonzales·Matt Kenworthy·Quinn M. Konopacky·Bruce Macintosh·Sarah E. Moran·Caroline V. Morley·Paulina Palma-Bifani·Laurent Pueyo·Bin Ren·Emily Rickman·Jean-Baptiste Ruffio·Christopher A. Theissen·Kim Ward-Duong·Yapeng Zhang
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Abstract

Young exoplanets provide a critical link between understanding planet formation and atmospheric evolution. Direct imaging spectroscopy allows us to infer the properties of young, wide orbit, giant planets with high signal-to-noise. This allows us to compare this young population to exoplanets characterized with transmission spectroscopy, which has indirectly revealed the presence of clouds, photochemistry, and a diversity of atmospheric compositions. Direct detections have also been made for brown dwarfs, but direct studies of young giant planets in the mid-infrared were not possible prior to JWST. With two exoplanets around a solar type star, the YSES-1 system is an ideal laboratory for studying this early phase of exoplanet evolution. We report the first direct observations of silicate clouds in the atmosphere of the exoplanet YSES-1 c through its 9-11 micron absorption feature, and the first circumplanetary disk silicate emission around its sibling planet, YSES-1 b. The clouds of YSES-1 c are composed of either amorphous iron-enriched pyroxene or a combination of amorphous MgSiO3 and Mg2SiO4, with particle sizes of less than or equal to 0.1 micron at 1 millibar of pressure. We attribute the emission from the disk around YSES-1 b to be from submicron olivine dust grains, which may have formed through collisions of planet-forming bodies in the disk.

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Kielan K. W. Hoch, Melanie Rowland, Simon Petrus, Evert Nasedkin, Carl Ingebretsen, Jens Kammerer, Marshall Perrin, Valentina D'Orazi, William O. Balmer, Travis Barman, Mickael Bonnefoy, Gael Chauvin, Christine Chen, Rob J. De Rosa, Julien Girard, Eileen Gonzales, Matt Kenworthy, Quinn M. Konopacky, Bruce Macintosh, Sarah E. Moran, Caroline V. Morley, Paulina Palma-Bifani, Laurent Pueyo, Bin Ren, Emily Rickman, Jean-Baptiste Ruffio, Christopher A. Theissen, Kim Ward-Duong, Yapeng Zhang. 2025-07-25. Silicate clouds and a circumplanetary disk in the YSES-1 exoplanet system. https://doi.org/10.1038/s41586-025-09174-w

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