Student researchers from Wimbledon High School GDST and Ursuline High School Wimbledon, along with Orbyts Fellows Jack Davey and Ruohan Liu from UCL Physics and Astronomy, have undertaken a research project to delve into the complexities of exoplanet atmospheric models. Their project focused on understanding and differentiating "degenerate models," where various atmospheric compositions can produce similar observational signals, which is crucial for accurate exoplanet characterisation and assessing their potential for habitability.

The research utilised Python simulations to create and analyse transmission spectra of exoplanet atmospheres under varying conditions. By adjusting variables such as gas composition, temperature, and pressure, they explored how degenerate atmospheric models could emerge. A key aspect of their methodology involved comparing multiple simulated spectra to understand how different parameter combinations could yield nearly identical observational signatures. To combat this, the students leveraged spectral data from various instruments on the James Webb Space Telescope (JWST).

The Wimbledon High School team analysed an NH3​ atmosphere and its best degenerate model, noting subtle misalignments in certain regions of the spectrum. The Ursuline High School team similarly found it challenging while trying to replicate the exact absorption features of a pure H2O atmosphere with CO2​, CH4​, and NH3. However,​ across the wavelength range of the JWST’s NIRSpec G395H instrument, a close fit was found, which suggested that distinguishing between a water-dominated atmosphere and a degenerate mix would be difficult with limited data from a single instrument.

Both research groups highlighted the importance of exoplanet atmospheres for understanding planetary conditions and their habitability. They underscored that different elements absorb and emit distinct wavelengths of light, enabling gas identification through light analysis. While the potential for discovering habitable exoplanets is exciting, the studies emphasised the critical need for more extensive data across various instruments and wavelengths to confirm the presence of specific atmospheric elements and "break degeneracies". This research represents an advancement toward more precise exoplanet characterisation, deepening our understanding of planetary formation and the conditions necessary for life beyond Earth!