Salt Clouds, Metal Rain and Rock Storms in the Deep Atmosphere of Jupiter and Implications on Exoplanets and Brown Dwarfs
Abstract
Salts, silicates and metals, such as KCl, ZnS, TiO2, Mg2SiO4, MnS, Fe, and Al2O3, condense as clouds in the deep atmosphere of Jupiter and greatly affect its chemical and dynamical structure. This new study has three motivations: (1) convective (rock) storms might trigger the observed internal mode oscillations of Jupiter (e.g., Gaulme et al. 2011; Markham and Stevenson 2018). (2) Salt grains could chemically modify the local plasma environment and produce possible signals for the JUNO microwave observations (Jansen et al. 2017). (3) Those high-temperature condensates are direct analogs of the clouds detected on hot Jupiters (e.g., Sing et al. 2016), directly imaged exoplanets (e.g., Zhou et al. 2016) and brown dwarfs (e.g., Apai et al. 2013), where the clouds form high in their photospheres. We first use a 1D microphysics model, CARMA (Gao et al. 2018; Powell et al. 2018), to simulate multiple cloud layers of salts, silicates and metals above 104 bar. TiO2 and KCl self-nucleates to form condensation nuclei for the other vapors to condense. Iron droplets can grow up to sub-milimeter size and rain down and evaporate at 104 bar. Mg2SiO4 is the most abundant cloud species, extending from 103 bar to 1 bar. The micron-sized silicate and salt grains might serve as the seeds for the water cloud formation. We then use a dynamical model, SNAP (Li and Chen 2018), to simulate the silicate thunderstorm. Latent heat release from the silicate condensation and deep convective flux drive the cloud-level moist convection. Jupiter's silicate "hydrological cycle" is found to be several orders of magnitude larger than the water hydrological cycle on Earth. We consider the convective storm as a heat engine and use the CAPE (convective available potential energy) to estimate the mechanical work done by the storm. The total available energy of a single rock storm can reach 1026 erg but it depends on the area fraction of the convection. Our ongoing 3D convection simulations will shed more light on the power from the storm to excite possible seismic modes on Jupiter.
- Publication:
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AAS/Division for Extreme Solar Systems Abstracts
- Pub Date:
- August 2019
- Bibcode:
- 2019ESS.....432917Z