26 November: Cathal Maguire

Speaker: Cathal Maguire (Dublin)

Date: Tuesday 26 November 2024

Time: 15:00

Location: Physics 3.29

Probing the atmospheres of ultra-hot Jupiters at high-resolution

Ultra-hot Jupiters are a class of exoplanets that have challenged our understanding of planetary formation, atmospheric chemistry, and dynamics. These gas giants orbit their host stars on orbital periods of P ~ days, experiencing immense stellar irradiation, resulting in extremely high effective temperatures often exceeding 2000 K. The recent significant advancements in ultra-stable ground-based high-resolution spectrographs have propelled ground-based astronomy to the forefront of exoplanet detection and characterisation. Ground-based high-resolution spectroscopy has now been successfully used to further our understanding of these objects, allowing us to build a more complete picture of their atmospheric composition. I will present observations obtained using the ground-based high-resolution spectrograph ESPRESSO, installed at the Very Large Telescope (VLT), to monitor the atmospheric abundances, temperature, and dynamics of two archetypal ultra-hot Jupiters — WASP-121b and WASP-76b — over the timescales of months/years. Using a novel rotational broadening kernel, the atmospheric abundances and vertical temperature structure of WASP-76b were also monitored longitudinally across the planet's limbs. Multidimensional high-resolution studies such as this can be used in tandem with similar low-resolution studies to provide a more comprehensive understanding of the atmospheric dynamics and composition of ultra-hot Jupiters.