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J-M. Petit, A. Morbidelli (CNRS - OCA), J.E. Chambers (NASA Ames / Armagh Observatory)
The existence of the asteroid belt and of the Edgeworth-Kuiper belt, both dynamically excited and with a total mass that is only a small fraction of the original one, may provide several clues for understanding the formation phase of our Solar System. The large number of bodies in the belts make them statistically significant sets of evidence and should be considered as observational constraints to discriminate among scenarios of Solar System's primordial evolution.
In the recent years, it has been shown that planetesimals of Lunar to Earth mass could provide a large dynamical excitation to the small bodies that filled the early Solar System (Petit et al.). In the same time, the most recent and successful models for the formation of terrestrial planets assume the existence of an initially cold disk containing sub-Lunar to Martian size planetesimals extending interior to Jupiter down to 0.5 AU (Chambers and Wetherill). Integrating a disk of grivitationnaly interacting planetesimals with a set of test particles, we show that such a disk, while forming the terrestrial planets and clearing the asteroid belt from its largest planetesimals, is capable of exciting the remaining smaller bodies to large eccentricities and inclinations. The presence of asteroids interior of 3.28 AU and the lack of them outside this limit impose very strong constrains on the initial mass and size distribution of the planetesimals. A very robust result is the total clearing of the inner asteroid belt. Refilling of the inner belt by collisional fragmentation of a late planetesimal, like in the case of Saturn's rings could help solve that problem.
The planetary formation simulations encompassing the whole region up to Jupiter, we also study the transport of material throughout the inner Solar System delivery of volatils to the terrestrial planets. The latest results will be presented.
Chambers, J.E. and Wetherill G.W. (1998), Icarus 136, 304-327
Petit, J-M., Morbidelli, A. and Valsecchi, G.B. (1999), Icarus, in press
The author(s) of this abstract have provided an email address for comments about the abstract: petit@obs-nice.fr