N-body interactions in proto-planetary disks: A study of collision velocities and impact angles

We show the distribution of collision parameters of planetesimals and planetary embryos in an evolving protoplanetary disk for various binary star–giant planet configurations. This statistical study provides an overview which and how many of the mutual disk object collisions have to be studied in more detail with SPH (smooth particle hydrodynamics) simulations and which can be approximated by a “corrected“ perfect merging process. In all configurations the gas has been already depleted and thus, only gravitational interactions are
taken into account.The binary star systems (with M = 1 M ⊙ for both) have seperations of 50 au or 100 au and eccentricities of 0.0 or 0.3. In the 50 au binary star the giant planet (with M ≈ MJ ) is placed at 3 or 5 au and in the 100 au binary systems at 4.5 or 6 au. In all configurations the planetsimal/embryo disk consists of about 1500 objects which move in nearly circular and planar orbits between the host-star and the giant planet. In the different simulations the disk objects have masses either from Ceres to Moon mass in case of planetesimals or from Moon to Mars mass in case of planetary embryos. To study the gravitational interactions of the whole system our recently developed GPU N-body integrator GANBISS is used, which is able to simulate some thousand (massive) disk objects in binary star systems.