The Irradiation-Driven Evolution of Gas-Giant Exoplanets

Author: Vissapragada, Shreyas

Year: 2022

Degree: Dissertation (Ph.D.)

Advisor: Knutson, Heather A.

Committee Members: Blake, Geoffrey A.; Knutson, Heather A.; Batygin, Konstantin; Yung, Yuk L.

Option: Planetary Sciences

DOI: 10.7907/73xn-xx35

Abstract

Nearly thirty years after their initial discovery, we now know of over five thousand extrasolar planets. Intensive efforts have been made to characterize the sizes, masses, orbits, and compositions of these new worlds, and the resulting population challenges our intuition from the Solar System. One striking feature of the exoplanet census is that the vast majority of known planets reside quite close to their host stars, with orbital periods of less than a hundred days. Our galaxy is replete with hot Jupiters, sub-Neptunes, and super-Earths orbiting their stars more quickly than Mercury orbits the Sun. These close-in planets are bombarded by high-energy stellar radiation, which heats their upper atmospheres and triggers mass loss via hydrodynamic escape. This means that planetary sizes, masses, and compositions can be substantially altered from their values at formation. This thesis presents five studies aimed at elucidating the irradiation-driven evolution of close-in extrasolar planets.

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