The spectroscopic observations of exoplanet atmospheres provide us with spectra, that is the breakdown of light into colours (wavelength or frequency). In other words, a spectrum tells us about the quantity of light per wavelength. When combined with complex atmospheric models, based on models of Earth’s atmosphere, astrophysicists are attempting to understand the physical-chemical processes at work in these atmospheres, such as the chemical composition (the molecules present), the dynamics, the presence of clouds, and so on.
An interview with the astrophysicist Pascal Tremblin, an exoplanet atmosphere modeller, explains how he pierces the mysteries contained in these spectra.
For more information: This video explains how researchers model the Earth’s atmosphere, with this model then being used by astrophysicists to study the atmospheres of exoplanets.