Abstract
Water clouds are expected to form on Y dwarfs and giant planets with Teff < 450 K, drastically altering their atmospheric compositions and thermal emission spectra. With JWST revolutionizing our observations of these ultra-cool worlds, we need to be prepared with a new generation of cloudy atmospheric models if we want to accurately characterize these objects. Here, I will present our investigation into the current prescription of water cloud formation and the improvements we have made based on a comparison with microphysical models. Our focus is to reduce the computational expense of microphysical water cloud models without compromising the accuracy of the cloud's optical properties and observational features on these cold substellar objects. Most importantly, I will discuss the differences we see in the simulated spectra between the current water cloud prescription and those with our new microphysically informed water clouds as we prepare for our upcoming JWST observations of WISE 0855, the coldest known brown dwarf. This new framework for modeling cloudy substellar atmospheres will enable us to explore this new frontier of characterizing temperate giant exoplanets with JWST.
