Effects of Collisions with Rocky Planets on the Structure of Hot Jupiters

The observed Hot Jupiters exhibit a wide range of physical properties. For a given mass, many planets have inflated radii, while others are surprisingly compact and may harbor large central cores. Motivated by this observational sample, this thesis considers the possible effects from collisions between Jovian planets and smaller rocky planets, and investigates whether these radius anomalies could be explained (in part) by such collisions. In this scenario, Jovian planets migrate through the circumstellar disk and enter into ∼ 4 day orbits, whereas the rocky planets (with mass mp = 0.1 − 20M⊕) migrate later and then encounter the Jovian planets. This thesis calculates the trajectories of incoming rocky planets as they orbit within the gaseous planets and are subjected to gravitational, frictional, and tidal forces. Such collisions cause the metallicity of the Jovian planet to increase, and if the rocky planets survive tidal disruption and reach the central regions, provide a means of producing large planetary cores. The energy released during these collisions provides the Jovian planet with an additional energy source and could inflate the radius; here we determine the radial layers where the kinetic energy is dissipated, including the energy remaining upon impact with the existing core. This process could have long-term effects if the colliding body deposits significant amounts of mass and energy deep in the interior, in regions of high opacity.