Raining Rocks: Collision, capture and ejection rates of comets in planetary systems

Impacts and ejections of comets and asteroids as a result of planet interaction play essential roles in forming planetary systems. They, for example, lead to the formation of Kuiper belts and Oort cloud-like structures, create interstellar comets, and can drastically change the development of life. In particular, the impacts of comets or asteroids onto planets can lead to complete atmospheric loss, jeopardizing the planet’s future evolution. We will present a novel analytic formulation for calculating the rates at which minor bodies collide, get captured, and are ejected into interstellar space due to the interaction with planets. By computing and comparing to a suite of detailed N-body simulations, we confirmed the accuracy of our analytic formulation. We first calculate the collision rates for the planetary systems detected by Kepler and TESS. To do this, we distributed minor bodies in Kuiper belt/Oort cloud-like structures adapted for each planetary system architecture. The resulting collision rates extend from 1e-9 up to 1e-2 comet/year. Hot-Jupiters experience the highest collision rates, which compromises the stability of their atmospheres. Second, we will present new estimations for capture rates of minor bodies by planets and the ejection rates into interstellar space. With our simple analytical formulation, we can predict planetary atmospheric loss, the formation of a family of comets orbiting planets, and the interstellar comet production rate for different planetary architectures. These predictions will guide future observational surveys to search for planets with stable atmospheres, cometary structures around planets, and objects in the interstellar space.