James Kirk

Dr. James Kirk is an Imperial College Research Fellow in the Department of Physics within the Faculty of Natural Sciences at Imperial College London. His research focuses on measuring the atmospheres of extrasolar planets ("exoplanets") to determine why exoplanets are so diverse compared to the planets in our Solar System, which lack equivalents to the most common types of exoplanets discovered.

Dr. Kirk obtained his PhD from the University of Warwick, where his thesis work focused on using ground-based telescopes to observe clouds and hazes within the atmospheres of short-period gas giant exoplanets (hot Jupiters). He subsequently worked as a postdoc at the Harvard-Smithsonian Center for Astrophysics, where he led new discoveries of escaping exoplanet atmospheres via measurements of exoplanetary helium and was a key member of the JWST Early Release Science Transiting Exoplanet Programme.

Dr. Kirk's research employs transmission spectroscopy to measure exoplanet atmospheric composition by analyzing how specific chemicals block starlight at different wavelengths during planetary transits. His work addresses fundamental questions about exoplanet diversity, with particular emphasis on:

• Comparing atmospheric compositions of aligned versus misaligned hot Jupiters to understand their formation histories
• Studying whether Earth-sized exoplanets can retain atmospheres despite intense stellar radiation
• Measuring atmospheric escape through exoplanetary helium observations
• Analyzing how atmospheric chemistry and physics vary with altitude

Dr. Kirk has developed the Tiberius data analysis pipeline for extracting exoplanet atmospheric spectra from raw JWST data. His research demonstrates the critical need for multiple transit observations and rigorous statistical analysis when studying small exoplanet atmospheres, as evidenced by his recent work on sub-Earth GJ 341b which showed the challenges of confirming atmospheric detections on small worlds.