Speaker
Description
Exoplanet atmospheres provide a direct window into planetary physics, chemistry, and long-term evolution. Through their composition and structure, we can probe processes such as irradiation, circulation, and mass loss, which ultimately shape how planets form and survive. Close-in gas giants, particularly hot and ultra-hot Jupiters, represent some of the most extreme laboratories for these effects. Intense stellar flux heats and inflates their atmospheres, drives chemical dissociation and ionisation, and can trigger hydrodynamic escape. These processes often produce extended exospheres and comet-like tails of evaporating gas, modifying transit signatures and enabling direct studies of star–planet interaction. Owing to their low bulk densities and expanded radii, these highly irradiated planets resemble marshmallows, while their proximity to the host star causes continuous atmospheric heating and loss — effectively turning them into “burning marshmallows”.
In this work, I investigate the physics of atmospheric escape and tail formation using theoretical modelling of radiation-driven outflows, gas dynamics, and species-dependent transport. I explore how neutral and ionised species evolve within the escaping flow and whether part of the evaporated material can remain gravitationally bound and migrate towards the host star. Under favourable conditions, heavy elements may accrete onto the stellar surface, potentially producing detectable photospheric contamination and linking atmospheric escape with star–planet mass exchange.