Exoplanet atmospheres is one of the most exciting areas of modern astrophysics. Thousands of exoplanets (planets around other stars) have been discovered in the last decades, and their diversity has been astounding. The next frontier in exoplanet research is to characterise this population of planets in detail through spectroscopy of their atmospheres. This allows us to investigate atmospheric physics in extreme environments, constrain the compositions of planetary atmospheres (which in turn can be linked to their interiors and formation), and to explore the diversity of planetary systems. We can also search for habitable - even inhabited - worlds!

Our group works primarily in observations of transiting planets - those which periodically pass in front of their host stars. Transiting planets play a special role in characterising exoplanets, as they are the only planets for which we can directly measure radii and masses (the latter via the complementary radial velocity technique). They also offer the only (current) avenue for studying temperate and/or cooler planets (other techniques such as direct imaging can only detect very young, gas-giants). We use world-leading optical and near-infared telescopes, including the James Webb Space Telescope (JWST), and the Very Large Telescope (VLT), to study transiting planet atmospheres. 

However, studying transiting planet atmospheres is extremely challenging, as we have to disentangle the exoplanet's tiny signal from its much brighter host star. Our group therefore has a key focus on the techniques used to extract exoplanet spectra from time-series observations, and in addition to observational techniques we develop novel Bayesian and machine-learning techniques to improve our ability to observe planetary atmospheres. For example, we have worked on Gaussian processes to improve our ability to model time-series observations (introduced to the field of exoplanets by Gibson et al. 2012), and have more recently focussed on Bayesian retrievals for high-resolution cross-correlation (Doppler-resolved) spectroscopy using ground-based observatories (e.g. Gibson et al. 2020; 2022). Much of our work currently focuses on hot Jupiters (gas-giants orbiting very close to their host stars) as these provide the ideal laboratories for testing new methodology and new atmospheric models; however, long-term we are interested in using JWST and the upcoming European-Extremely Large Telescope (E-ELT) to study the atmospehres of terrertrial planets. 

• If you are interested in joining our group as a PhD student or Postdoc, you can find further information here.
• You can find our group publications here.