Planetary Group Seminar: Gravoturbulent Formation of Planetesimals - Why Asteroids and Kuiper Belt objects are 100 km in size (H. Klahr)

Comets, asteroids and Kuiper Belt objects are left overs of building material for our earth and the other planets in our solar system. At the time of their formation these objects, called planetesimals, built up from icy and dusty grains. In our current paradigm of solar system formation it was turbulent flows and metastable flow patterns like zonal flows and vortices that concentrated mm to cm sized pebbles. What was missing until recently was a physically motivated prediction on the typical sizes at which planetesimals should form via this process. With the lastest series of simulations we were able to obtain values for the turbulent particle diffusion as a function of the particle load in the gas. Thus, we can predicts the initial size of planetesimals as result of a competition between gravitational concentration and turbulent diffusion. Based on these findings we develop a recipe to introduce planetesimal formation into population synthesis models for Exo-Planets.