Vertical mixing of mineral clouds in hot Jupiter atmospheres
Copernicus Publications (2026)
Abstract:
Recent JWST transmission and emission spectroscopic observation of hot Jupiters have demonstrated that sub-micron sized silicate mineral clouds may be common hot Jupiter atmospheres. In addition, ground-based high-resolution spectroscopic observations of both transit and eclipse have implied horizontal asymmetries that may be amplified by clouds. Silicate mineral clouds have long been predicted to form and persist on the nightside and western dayside of hot Jupiters by cloud microphysical models and 3D General Circulation Models. Given the capability of current ground-based high resolution spectrographs, complementary JWST observations, as well as recent advancements in modelling techniques, the time is right to determine the prevalence and spatial and particle size distribution of mineral clouds across the parameter regime of hot Jupiters. This effort will provide a detailed test of our present theoretical understanding of cloud nucleation, transport and growth processes, and the radiative feedback of clouds on the atmospheric circulation and climate of hot Jupiters. In this work, we present a combination of analytical and numerical models of the vertical mixing of mineral clouds in hot gas giant atmospheres. Our scaling analyses naively predict that clouds of a broad range of particle sizes (up to 10 microns) should be well-mixed throughout gas giant atmospheres to low pressures (~0.1 mbars). However, the local nature of vertical mixing in more detailed three-dimensional simulations prevents such well-mixed micron-sized mineral clouds in many cases. In addition, we hypothesise that fragmentation may play a role in setting the characteristic maximum particle size of silicate mineral clouds in hot Jupiter atmospheres, much like it impacts the build-up of silicate grains in protoplanetary disks. We predict how mixing scales with cloud particle size and composition using analytic theory and three-dimensional numerical simulations including cloud tracers. We discuss implications for ground-based high resolution characterisation of hot Jupiters, especially with time-resolved spectroscopy.Vertical Distribution of Cloud and Ammonia in Jupiter’s equatorial atmosphere revealed by co-analysis of VLT/MUSE, Cassini/VIMS and Juno/JIRAM
(2026)
Abstract:
A Processing Workflow for Cassini VIMS Jupiter Cubes
The Astrophysical Journal Supplement Series American Astronomical Society 285:1 (2026) 30
Abstract:
We present a calibrated catalog of Cassini Visible and Infrared Mapping Spectrometer (VIMS) observations of Jupiter, together with the processing workflow used to generate the final publicly available products. Starting from the raw VIMS cubes, the workflow produces radiometrically consistent multiextension Flexible Image Transport System files and includes a revised visible-channel calibration, a revised infrared-channel calibration that resolves a subset of problematic cases not satisfactorily treated by the standard Integrated Software for Imagers and Spectrometers pipeline, corrections for pointing-related misalignments between spectral cubes and geometric backplanes, and customized dark signal correction strategies. The final products include calibrated spectral cubes together with geometry backplanes and wavelength information for subsequent scientific analysis. We assess the consistency of the calibrated products through internal validation tests and comparisons with independent reference spectra from the literature. The resulting products provide a uniform and validated data set of Cassini VIMS Jupiter observations for community use. The full catalog is available as a public dataset at doi:10.5281/zenodo.19223781.
Flow-Driven Limb-Asymmetry of Haze Distribution Part I: An Analytical Framework for Predicting the Size Distribution of Photochemical Hazes Across the Two Limbs of hot-Jupiters
Accepted for publication in Monthly Notices of the Royal Astronomical Society
Abstract:
Photochemical haze, a common aerosol type expected to form in the atmospheres of hot-Jupiters, can become concentrated to different extents between the morning and evening limbs depending on the balance between advection, gravitational settling, and radiation pressure. We present a analytical framework incorporating the effect of gravity, planetary radius, and stellar flux, alongside the particle size of the haze on its resulting relative distribution between the two limbs. Using this framework and further comparing with 3D climate simulations, our framework provides a reasonable first-order estimate of the maximum radius of haze particles which would reach the morning limb and subsequently be trapped by the nightside gyres, resulting in a higher or comparable concentration of haze over the morning limb compared to the evening limb for a given hot-Jupiter atmosphere. We find that the framework performs best for higher-gravity planets, where the transport of haze particles is more strongly controlled by gravitational settling and therefore less sensitive to the approximations made in describing the atmospheric circulation. We further show that for low-gravity hot-Jupiters, even large haze particles can be readily transported to the morning limb before being removed by gravitational settling, whereas for high-gravity hot-Jupiters only small particles can survive transport to the morning limb. Our novel framework provides a rapid way to understand the transport of haze and plan limb asymmetry observations with JWST, constraining the parameter space exploration for full-scale computationally expensive 3D simulations.
Direct Imaging Discovery of Giant Exoplanet $β$ Pictoris d: A Decade-Long Game of Hide-and-Seek
(2026)