Remote sensing alien clouds and chemistry with JWST

The last decade has seen the advent of direct characterisation of the atmospheres of giant exoplanets via high contrast imaging and spectroscopy. However, interpreting these data can be problematic due to their sparse nature and poor signal to noise resulting from the challenging nature of the observations. Unhindered by bright host stars but sharing the same temperatures, free floating brown dwarfs and planetary mass objects have become crucial laboratories for understanding the complex physics and chemistry of these atmospheres.

Dr Burningham has developed software (nicknamed "Brewster" - see Burningham+ 2021; Gonzales+ 2020 , 2021; Calamari+ 2022, Vos+ 2023) for studying these atmospheres using spectral inversion (also known as retrieval analysis) with a particular emphasis on understanding their clouds, chemistry and thermal structure. Dr Burningham is coordinating retrieval analysis for a range of approved JWST Cycle 1 and Cycle 2 programmes.

In this project, we will seek to identify the specific cloud species in a set of benchmark brown dwarfs that orbit FGK stars that will be observed during 2024 on JWST Cycle 2 approved programme 3670. We will place the chemistry of these clouds within the context of the expected bulk composition of these atmospheres based on that of their host stars.

Non-equilibrium chemistry and vertical transport are also expected to play a key role, and will also be constrained by our analysis. This work will aim to place firm constraints on our ability to infer bulk compositions for extrasolar worlds based on atmospheric observations.