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Outer Solar System formation and evolution

Morbidelli, A (Observatoire de Nice)
Monday 09 November 2009, 14:00-14:50



I will discuss how the giant planets of our solar system could avoid Type II migration towards the Sun. The dynamics, ruled by the interaction of Jupiter and Saturn with the gas disk would have left the four giant planets on fully resonant orbits with very small eccentricities and inclinations. After the disappearance of the gas disk, the interaction of the planets with the planetesimals extracted the former from their original quadruple resonance and led to a late but short phase of dynamical instability in the planetary motion. The current orbital configuration of the giant planets could then be achieved from the gravitational interaction between the planets and the disk of planetesimals. In particular, we will discuss how the amplitudes of the secular modes that characterize the current secular motion of the planets could be achieved. In the scenario where the dynamical instability of the giant planets occurred late, which is tempting to explain the origin of the so-called Late Heavy Bombardment, the orbital stability of the terrestrial planets is at risk. I will discuss how the terrestrial planets could have survived the sweeping of powerful secular resonances through their region and eventually acquire their current orbits. Constraints from the orbital distribution in the asteroid belt will also be discussed, as well as the origin of the orbital architecture of the Kuiper belt and of the systems of irregualr satellites.

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