DDP

Abstract

In this talk, I will review the main features of gravitational instabilities in gaseous discs. I will discuss the conditions under which protostellar discs are expected to be unstable and describe their evolution. I will discuss the role of gravitationally induced structures in the formation of planetesimals, also in the light of recent developments on the structure of self-regulated protostellar discs. I will show that planetesimal formation through gravitational instabilities in the gas disc can only occur at large radii, beyond a few tens astronomical units and discuss its implications.