Speaker
Description
The discovery of planets around other stars (exoplanets) has fundamentally changed our view of the possible types of planets. With the discovery of a diverse population of planets, a class of highly irradiated gas giants has emerged that are unlike any planet in our solar system.
Ultra-hot Jupiters offer the opportunity to learn about the chemistry, thermal structure and dynamics in atmospheres at high temperatures: They are particularly amenable to transmission spectroscopy because they are in close orbits around their host stars with periods of only a few days, which in turn causes high equilibrium temperatures and simplifies the chemistry. Expected to enter tidal synchronisation soon after their formation (Rasio et al. 1996; Showman & Guillot 2002), the atmospheres of ultra-hot Jupiters are divided into a permanently irradiated hot day side and a cooler permanently dark night side, causing extreme temperature and chemical fluctuations, so that the thermal dissociation of molecules, partial thermal ionisation of atomic species and thermal inversions induced by metals or their oxides become important (Lothringer et al. 2018; Kitzmann et al. 2018; Parmentier et al. 2018; Arcangeli et al. 2018).
Thanks to high-resolution transmission spectroscopy, we are able to study atmospheric composition and routinely detect metals, revealing dynamics and atmospheric stratification as well as chemical inhomogeneities in the atmospheres of ultra-hot Jupiters as predicted by theoretical studies (Wardenier et al. 2021). The dynamics as represented by super-rotational winds and the presence or absence of certain species contribute to a broader picture of the atmospheres of these exoplanets.
During my talk, I will present the analysis of a transmission spectrum of an ultra-hot Jupiter, focusing on how the aforementioned effects are visible in our detections and what they tell us about the chemical and dynamical properties of the atmosphere.
