Abstract: The discovery of a large number of extrasolar planets has demonstrated that our own system is not "typical". Exo-planetary systems can be very different from our own, and diverse from each other. Understanding this diversity is a major goal of modern planetary science. The formation of planetary systems is not fully understood, but major advances have been obtained in the last 10 years. New concepts have been proposed, such as the streaming instability for the formation of planetesimals and pebble accretion for the formation of protoplanets. It is also now clear that planets forming in the proto-planetary disks have to migrate during their accretion, if their mass exceeds a few times the mass of Mars. Accretion and dynamical evolution are therefore very coupled processes. This leads to complex evolutions, very sensitive to initial conditions and fortuitous events, that are the key to understand the observed diversity of planetary systems. The early formation of Jupiter and its limited migration due to the formation of Saturn are two fundamental ingredients that determined the basic structure of the Solar System. There is also evidence that the vast majority of planetary systems become unstable after the removal of the protoplanetary disk. The effects of this instability are very different depending on the masses of the planets involved. Our Solar System also experienced a global instability, but fortuitously, our giant planets did not develop large orbital eccentricities.

Bio: Dr. Morbidelli is one of the world's top experts in the dynamical history of the solar system (as one example, the Nice model of giant planet instabilities as the origin of the late heavy bombardment). He is also an expert in the area of planet formation writ large, with numerous contributions on the origins of planetary systems. He won the Urey Prize from the planetary science division of the American Astronomical Society in 2000, the Grand Prix Mergier-Bourdeix from the Académie des Sciences in 2009, the CNRS Silver Medal in 2019, and is a member of the Collége de France.

The talk will be followed by refreshments and time for discussion until 5:00 p.m.

The Departments of Physics, Astronomy, CLASP, and Earth & Environmental Science have jointly established a new initiative named the Center for Habitable Planetary Systems (CHPS).