Overcast on Osiris: 3D radiative-hydrodynamical simulations of a cloudy hot Jupiter using the parametrized, phase-equilibrium cloud formation code EddySed

Abstract

We present results from 3D radiative-hydrodynamical simulations of HD 209458b with a fully coupled treatment of clouds using the EddySed code, critically, including cloud radiative feedback via absorption and scattering. We demonstrate that the thermal and optical structure of the simulated atmosphere is markedly different, for the majority of our simulations, when including cloud radiative effects, suggesting this important mechanism can not be neglected. Additionally, we further demonstrate that the cloud structure is sensitive to not only the cloud sedimentation efficiency (termed f sed in EddySed), but also the temperature-pressure profile of the deeper atmosphere. We briefly discuss the large difference between the resolved cloud structures of this work, adopting a phase-equilibrium and parameterised cloud model, and our previous work incorporating a cloud microphysical model, although a fairer comparison where, for example, the same list of constituent condensates is included in both treatments, is reserved for a future work. Our results underline the importance of further study into the potential condensate size distributions and vertical structures, as both strongly influence the radiative impact of clouds on the atmosphere. Finally, we present synthetic observations from our simulations reporting an improved match, over our previous cloud-free simulations, to the observed transmission, HST WFC3 emission and 4.5 µm Spitzer phase curve of HD 209458b. Additionally, we find all our cloudy simulations have an apparent albedo consistent with observations.

Cloud property trends in hot and ultra-hot giant gas planets (WASP-43b, WASP-103b, WASP-121b, HAT-P-7b, and WASP-18b)

“…Simulations using GCMs requires extensive computational resources, in particular if the radiation hydrodynamics is solved consistently with the gas chemistry and actual cloud formation modelling. Therefore, it is unsurprising that all exoplanet models apply a cloud parameterisation of some sort (Dobbs-Dixon & Agol 2013; Charnay et al 2018;Mendonça et al 2018;Lines et al 2019;Roman et al 2021;Parmentier et al 2021). Grids of GCM simulations are often run as completely cloud free or as opacity species only with cloud properties derived in postprocessing (e.g.…”

Aerosols in Exoplanet Atmospheres

“…For 3D aerosol models, Lines et al (2019) juxtaposed the advection of cloud distributions computed from DRIFT by a GCM with stationary cloudy atmospheric columns computed by the Ackerman and Marley (2001) In addition to comparisons of models of similar complexity, lessons learned from complex aerosol models should be incorporated into simpler models used in retrievals and radiative-convective equilibrium models so that they can be made more physical and predictive, while allowing for connections between more subtle microphysical processes and exoplanet observations. Gao et al (2018) attempted to place the sedimentation efficiency parameter of the Ackerman and Marley (2001) model into the context of microphysical processes by comparing it to CARMA for different planetary and aerosol parameters, but a more systematic and extensive effort is needed.…”

Atmospheric Dynamics of Hot Giant Planets and Brown Dwarfs

“…Similarly, considering a species that is not present in the atmosphere can lead to a strong overestimate of the cloud radiative feedback. As shown by Lines et al (2019), using two different cloud parametrisation can lead to very different radiative feedback, thermal structure and observational consequences.…”