Abstract

How km-sized planetesimals are formed from dust grains remains a mystery, with many barriers to growth preventing growth by coagulation beyond mm-sizes. For this reason, collective mechanisms that concentrate dust grains sufficiently to allow gravitational collapse to jump the intermediate sizes and form planetesimals directly are appealing. While protoplanetary discs are young and massive they can go through a phase in which their own self-gravity is important driving spiral waves that heat the disc and balance cooling. The large disc masses and strong self-gravity mean that a only a relatively modest concentration of dust is needed for gravitational collapse, but the highly dynamic environments makes self-gravitating discs harsh locations for grain growth. I will present on going work on the dynamics of dust in these discs and discuss the conditions required for planetesimal formation.