Architecture and evolution of planetary systems

In this 8th session of the internet-based live lectures between Universities and Institutes, prof. Ewa Szuszkiewicz discusses the structure and dynamical evolution of planetary systems. The lecture starts with an introduction to the motion of planets according to the physical laws of the Newtonian mechanics, from which the Kepler's laws originate. The characteristic properties of our Solar System are summarised and compared with those of some extrasolar systems like 51 Pegasi, Kepler-36, Kepler-20, Kepler-11 and HR 8799. These systems have been especially selected in order to bring out the concept of planetary migration, a process which takes place during the early phases of the evolution of planetary systems. The role of a subtle gravitational effect called mean-motion resonance in the chosen examples of planetary systems is particularly stressed. Mean motion resonances might be a key player in shaping planetary architectures. The lecture ends up with the presentation of a new class of planetary systems in which the planets are orbiting around binary stars, focusing on one of the best examples of such systems known at the moment, namely Kepler-47.