Modeling the formation of a giant planet with collisions among planetesimals

During the process of giant planet formation, the planetesimals relative velocities are increased due to the gravitational perturbations produced by the growing planet. The equations of the planetesimals relative velocities usually used in the literature are revised. We study the validity of these equations as the orbital eccentricities of planetesimals increase. A change of regime is produced in planetesimals collisions, from coagulation at low relative velocities to fragmentation as their velocities grow. Although models of planetary formation that include planetesimal fragmentation consider the specific impact energy for a fixed velocity and composition, this energy is a function of these physical properties. We study the formation of a giant planet at 5 AU incorporating such dependences.