Where is the iron in cloudy atmospheres of Jupiter-sized exoplanets?

With the new generation of space missions like JWST, CHEOPS and PLATO, the characterisation of gas giant planets like WASP-17 b, WASP-107 b, WASP-39 b, HD189733 b and WASP-43 b has become possible. The 3D General Circulation Model ExoRad is used to simulate 3D atmosphere structures for exoplanets orbiting M-, K-, G-, F- and A-type stars.  1D profiles are extracted across different locations as input for our kinetic, non-equilibrium cloud model to gain insight on the chemistry and dynamic behaviour of their atmospheres. The Jupiter-sized planets are tidally locked and a wide range of global temperatures (TGlobal = 400K-2600K), resulting in a grid of a total of 60 different simulated planets. This grid serves as input interpretation for JWST, CHEOPS and PLATO data.

Through this hierarchical modelling approach, a deeper understanding of the host star’s influence on the thermodynamic structure of these planets and its effect on the clouds is obtained. Models of formation through nucleation, surface growth, evaporation, and gravitational settling, consistent with element conservation, are used to calculate the nucleation rate, the local average particle size and the cloud particle composition.

A systematic comparison of atmosphere and cloud structures is possible based on our exoplanet model grid. Here, an in-depth examination of the iron composition of the cloud particle was conducted, focusing on where it is found in the atmosphere across different pressure regimes. This work is part of our science support efforts within the PLATO WPs 116700 and 116800.