Abstract
Planetesimals are the first macroscopic objects to form in a protoplanetary disk. Asteroids and trans-Neptunian objects are the remnants of the initial population of planetesimals in the circumstellar disk. The collective dynamics of dust particles and their influence on gas dynamics can, in some cases, lead to the creation of self-gravitating clusters which then collapse to give rise to planetesimals around 100 km in size.
