As part of his PhD, Pierre-Alexis works on the atmosphere characterization of sub-Neptunes. Sub-Neptunes are a mysterious and intriguing class of exoplanets. These planets, which are just slightly smaller in size than Neptune, represent the most abundant type of exoplanet in our galaxy. However, no sub-Neptune is found in our own solar system, which leaves us with many questions regarding their formation and their composition. What are they made of? Why are they so frequent in our surveys? In order to try and answer these questions, Pierre-Alexis uses space-based observatories such as Hubble and JWST to perform atmosphere characterization of transiting sub-Neptunes. This method uses the light received from the system at multiple wavelengths to reveal which molecules are present in sub-Neptunes’ atmospheres and infer their composition. Through such studies, Pierre-Alexis is able to learn the dominant molecules of sub-Neptunes’ atmospheres and to infer the temperature, clouds and winds on the planets based on comparison to complex 1D and 3D models of sub-Neptunes. Current and future targets on Pierre-Alexis’s radar include TOI-824b, GJ9827d and LP791-18c.
Recently, Pierre-Alexis has been involved in multiple JWST research projects. As a member of the exoplanet Early Release Science (ERS) community, he participated to the very first atmosphere characterization of an exoplanet, WASP-39b, with JWST. Moreover, Pierre-Alexis is a member of the NEAT team in iREx, and is participating in a deep JWST study of the exciting TRAPPIST-1 system.
Pierre-Alexis started his PhD with Prof. Björn Benneke in May 2021. He obtained his undergraduate degree in Honours Physics and Mathematics from McGill University in May 2020 and then started a Master’s degree with Prof. Benneke before fast-tracking to the PhD one year later.