Abstract

In this Dynamics Lunch discussion, I will explore the onset and evolution of gravitational instability in gaseous discs—focusing primarily on protostellar systems—and draw parallels with spiral galaxies.

Gravitational instability is thought to be the main driver of angular momentum transport in young protostellar discs, and to play an important role in the process of planet formation. I will discuss the key triggers of instability—rapid cooling and/or external mass loading—and introduce how techniques from galactic dynamics can be used to understand the morphology and kinematics of spiral waves in protostellar environments.

This discussion aims to bridge to connect galactic and protostellar discs, demonstrating that “surfing” spiral density waves provides a unified framework to understand structure and formation across different scales.