Ultra-hot Jupiters through the eye of JWST!

Ultra-hot Jupiters (UHJs) are thought to have undergone extreme formation and evolution, making them ideal laboratories for uncovering the phenomena that determined their origin and atmospheric structure. The James Webb Space Telescope (JWST) provides an unprecedented capability to study the chemical and physical properties of these exoplanets in exquisite detail. With its broad spectral coverage and high-precision instruments operating from the near- to mid-infrared, JWST offers an unparalleled ability to detect key molecular features in these extreme atmospheres, as well as cloud structures and atmospheric dynamics, using techniques such as transmission and emission spectroscopy.

In this talk, I will present the analysis of JWST transmission and emission spectroscopic observations of three particularly intriguing UHJs. I will discuss data reduction and analysis techniques, combining two independent reduction channels with multiple detrending methods, as well as atmospheric modeling approaches, including retrieval analyses. Taking advantage of the exceptional quality of JWST observations, we have detected several key molecular species in these extreme atmospheres and precisely determined their abundances, in addition to constraining cloud composition and structure. I will show how these precise measurements translate into robust estimates of atmospheric metallicities and, importantly, C/O ratios, a crucial indicator of planetary formation and evolutionary histories . Finally, I will reflect on how these comprehensive UHJ chemical inventories serve as valuable benchmarks for next-generation atmospheric models and theories of giant planet evolution.