Proefschrift
Modelling escaping atmospheres of highly irradiated exoplanets
Exoplanets close in to their host star receive high levels of extreme ultraviolet (EUV) irradiation, capable of heating and ultimately driving the hydrodynamic escape of their atmospheres.
- Auteur
- A.P. Allan
- Datum
- 25 februari 2026
- Links
- Thesis in Leiden Repository
This atmospheric escape has indeed been detected for a growing number of highly irradiated exoplanets, via the method of transmission spectroscopy. Owing to its ability to be observed using ground based telescopes, the HeI triplet at 1083nm has become the most popular spectral feature for detecting atmospheric escape via transmission spectroscopy, overtaking hydrogen's Lyman-alpha line. This thesis is a theoretical study into the hydrodynamic atmospheric escape of highly irradiated exoplanets, performed using 1-D, self-consistent, numerical modelling. How atmospheric escape evolves over an exoplanet's lifetime, how observable hydrogen and helium transit signatures are affected, and how a stellar activity cycle can influence both the escape and helium transit signature, are all explored.