Interior and Evolution of Giant Planets and the Fate of Planetesimals
in the Early Solar System

Tristan Guillot
Observatoire de la C\^ote d'Azur, Nice, France
(guillot@obs-nice.fr)

Abstract:
Jupiter and Saturn consist mainly of hydrogen and helium. Yet the
heavy elements they possess are the key to understanding their
formation. I will present new constraints on their internal
composition and structure, obtained both from interior and evolution
models of these planets. These predict that Jupiter and Saturn possess
a central core of 0 to 10, and 6 to 17 
M$_\oplus$, and a total mass of heavy elements of $11-42$ and $19-31$ 
M$_\oplus$, respectively. Constraints on the structure of lighter
Uranus and Neptune will also be discussed. 

I will also present results of new numerical integrations of
the dynamical evolution of particles (planetesimals or cometesimals)
in the early outer Solar System. The ultimate fate of the particles
(ejection, transport to the Oort Cloud, impact with planets or
leftovers in dynamically stable regions) critically depends on the
characteristics of the young growing giant planets: their masses and
radii. Constraints provided by interior and evolution models of the
giant planets thus help to learn about their formation
mechanisms, the characteristics of the early protosolar nebula, and
the formation/storage of comets and planetesimals.