Turbulent Disks are Never Stable: Fragmentation and Turbulence-Promoted Planet Formation

Understand

A fundamental assumption in our understanding of disks is that when the Toomre Q>>1, the disk is stable against fragmentation into self-gravitating objects (and so cannot form planets via direct collapse).

• But if disks are turbulent, this neglects a spectrum of stochastic density fluctuations that can produce rare, high-density mass concentrations.
• Here, we use a recently-developed analytic framework to predict the statistics of these fluctuations, i.e.
• the rate of fragmentation and mass spectrum of fragments formed in a turbulent Keplerian disk.