Formation of super-Earths in a protoplanetary disk

This is a simulation of the process of formation for a planetary system with close-in super-Earths.

The simulation begins with 125 planetary embryos, each with 0.4 times the mass of the Earth. The gray region shows the height of the protoplanetary disk. At the beginning of the simulation the embryos have strong gravitational encounters that increase their orbital inclinations (y-axis) and leads to collisions. After the embryos merge into larger bodies, interactions with the disk cause the eccentricities and inclinations to drop and the planets form a chain of mean motion resonances. Planets also experience torques from the disk that remove orbital angular momentum which causes the planets to drop to lower orbits. While the planets migrate through the disk, they accrete gas from the disk. The color of each body shows the fraction of their mass that is in the gaseous envelope.

The disk dissipates after 5 Myr. With the disk gone, the planetary system becomes dynamically unstable and two new waves of giant impacts occur. This leaves behind a planetary system with larger planet masses, smaller gas envelopes, and higher mutual inclinations.