Chemistry of (exo)planetary atmospheres

The past twenty years have revealed an amazing diversity of exoplanets beyond the narrow confines or our Solar System. Current observational technologies have even allowed us to start probing into the atmospheres of a tiny handful of the >5,500 known exoplanets, and translate their spectroscopic features into both physical (dynamics, pressure and temperature) and chemical (molecular abundances) properties. Such atmospheric characterisation is currently proceeding at a slow pace, but observations to date suggest that exoplanets possess highly diverse, often unexpected atmospheric chemistries. The James Webb Space Telescope (JWST), launched in 2022, already provides glimpses into these atmospheres over a wide range of wavelengths and at a very high spectral resolution. Most excitingly, the JWST have the capabilities to probe the unclear boundary between rocky planets and gas giants, and may even investigate the best potentially habitable terrestrial exoplanet targets, therefore propelling the tentative detection of Life and its building blocks outside our home planet.

Our team within the Astrophysics group (the Exeter Exoplanet Theory Group (EETG, exoclimatology.com) has been developing over the past years a suite of flexible multi-dimensional numerical tools, covering a wide range of complexities, to support our understanding of the key physical and chemical processes at play within (exo)planetary atmospheres and to investigate how these processes behave and translate to observable features in different planetary environments, including some of the recent findings by JWST. Our modelling framework includes a flexible 1D/2D radiative-convective chemical kinetic model (ATMO) and the state-of-the art 3D Unified Model (UM) of the Met Office, which both includes sophisticated treatments of radiative transfer and chemistry.

Potential projects include (but are not limited to) your involvement in (1) the continued development of multidimensional chemical models robust and reliable enough to interpret current and future high-resolution observations, possibly by extending our understanding of the impact of photochemistry and cloud chemistry on readily observable atmospheric features, or (2) in the creation of the next generation of retrieval framework, including multidimensional non-equilibrium heterogeneous chemistry, that would allow a better analysis and interpretation of observations than is possible today on the basis of traditional one-dimensional free-chemistry or equilibrium gas-only assumptions.

Whatever the selected project, it will provide you with the opportunity to develop skills in programming and high-performance computational modelling, as well as experience relevant to both astrophysics and atmospheric science. Your project will be part of a wider programme involving a diverse team working on different aspects of the modelling of (exo)planetary atmospheres (e.g. dynamics, radiative transfer, climate), which you will be an integral part of. Although ample training opportunities will be offered, the successful candidate will have some experience in programming and a degree in Mathematics, Physics or Natural Sciences (some background in Chemistry is welcome, but not mandatory).