Abstract:
The atmospheres of exoplanets, planets orbiting stars beyond our solar system, can be examined via observational measurements and theoretical interpretations to ultimately understand how the conditions and environment of a planet effect its climate. Exoplanets are at the forefront of public interest in space and have emerged as a leading scientific field over the past decade. In this talk I will introduce you to the history and study of exoplanets and their atmospheres from discovery, early characterization efforts with Hubble and to the latest observations with JWST - the largest telescope ever launched into space.
In the short time since the start of JWST’s science operations, it has caused a paradigm shift in the information and understanding of giant planet atmospheres. The spectroscopic IR capabilities have revealed absorption from H2O, CO2, and CO with exquisite precision, provided the first look at elusive methane absorption, and shown a diversity of photochemistry and disequilibrium processes at play in giant planet atmospheres. Previously obscuring aerosols that plagued Hubble's UV-optical spectra are revealing themselves via distinct absorption and emission in the mid-IR confirming for the first time in irradiated exoplanets theoretical predictions of cloud formation. But JWST alone cannot fully constrain the atmospheric complexity of exoplanets. I will show how Hubble and JWST are needed to work together to understand these exotic atmosphere and I will present a case study of one such planet which is revealing the roles of clouds and chemistry in exoplanet atmospheres and the feedback imparted between composition, dynamics, and detectability.
Exoplanet case study references: Grant et al. 2023, ApJL; Louie et al. 2024, AJ, Valentine et al. 2024, AJ; Gressier et al. 2025, AJ; Lustig-Yaeger et al. 2025, ApJL; Alderson et al. in press; Valentine et al. in review; Wakeford et al. in prep; Lewis et al. in prep.
Funding: HR Wakeford is funded by UK Research and Innovation (UKRI) framework under the UK government’s Horizon Europe funding guarantee for an ERC Starter Grant [grant number EP/Y006313/1]
Biography:
Hannah Wakeford is an Associate Professor in Astrophysics in the School of Physics at the University of Bristol where she leads the exoplanet timeseries characterization team. She is an expert in observations of exoplanets with space-based observatories and has amassed over 1000 hours of JWST time in the past 5 years to make state-of-the-art measurements. Hannah is also an expert in the role of aerosols in planetary atmospheres. Hannah is currently the lead of a UKRI Frontiers Research Grant (formerly European Research Starting Grant) to examine the 3D properties of exoplanet atmospheres through observations with Hubble and JWST. In this work Hannah and her team (at Bristol, and collaborators internationally) will extensively measure the transmitting and emitting atmosphere of a set of exoplanets to understand the links between their properties and measured chemistry and dynamics. Her work has been recognised with many notable awards and you can often find press releases on her teams discoveries on the University of Bristol news pages.
Hannah is also a leading science communicator and has appeared on a number of TV and radio shows. She is the host of Exocast: The exoplanet podcast and also co-authored a popular science book on the history of the universe with Prof Chris Lintott and Dr Brian May (of Queen fame).