Exoplanet atmospheric spectroscopy

Observations of exoplanet atmospheres are key to understanding their chemical composition, climate, and potential habitability. Our team is interested in constraining the key parameters of exoplanetary atmospheres, including the chemical composition and temperature structure. To achieve this goal, we analyse the transmission spectra of exoplanets taken by space-based observatories. Some of our research activities in this area include the reduction and analysis of exoplanet transit data from the James Webb Space Telescope, and the application of machine learning in the atmospheric retrieval of simulated data for the Ariel mission.

Optical depth of exoplanet transmission spectra for varying pressure-temperature profiles and cloud-deck altitudes. Reproduced from Schleich et al. (2024).

Exoplanet atmospheric modelling

Atmospheric observations help identify the presence of different chemical species on a planet's atmosphere. However, interpretation of these observations, and understanding the physical and chemical processes that produce the observed signatures rely on atmospheric models. We use the 1D atmospheric model Kompot to study the thermo-chemical structure of planetary atmospheres. Some of our ongoing numerical projects include, atmospheric survivability of N2 and CO2 atmospheres on Earth-sized exoplanets, and atmospheric photochemistry in gaseous exoplanets.

Habitable zone atmosphere retention distance — Atmosphere retention distances for different stellar masses for slowly rotating stars at an age of 5000 Myr. The green shaded area indicates the HZ. Symbols indicate scheduled JWST targets, with triangles highlighting eclipse observations. For clarity, the system’s name is not repeated for each planet in the TRAPPIST-1 and TOI-700 systems. Reproduced from Van Looveren et al. (2025).

Stellar magnetic activity

A vast majority of exoplanets are found around cool main-sequence stars, spectral type F V to M V. Cool stars are magnetically active, and their magnetized winds and high-energy radiation in the X-rays and the ultraviolet wavelength are responsible for atmospheric heating, ionization, photochemistry, haze formation, and escape of atmospheric species. Our research is aimed at understanding the relationship between magnetic field, winds and high-energy radiation of exoplanet host stars and stellar properties. Our team is leading a Hubble Space Telescope observing program to monitor the ultraviolet flux of exoplanet host stars (program ID: 17794). We are also involved in multiple other observing programs to monitor the magnetic field and high-energy activity of exoplanet host stars.