1301.2064 (Mir Abbas Jalali)

Global streaming instability in ring-shaped protoplanetary disks    [PDF]

Mir Abbas Jalali

We use the Fokker-Planck equation and model the dispersive dynamics of solid particles in annular protoplanetary disks whose gas component is more massive than the particle phase. We model particle--gas interactions as hard sphere collisions, determine the functional form of diffusion coefficients, and show the existence of global unstable modes in the particle phase. These modes have spiral patterns with the azimuthal wavenumber $m=1$ and rotate slowly. We show that in ring-shaped disks, solid particles subject to gas drag never fall into the central star and instabilities occur for particles of all sizes. Therefore, planetesimals and planetary cores can be efficiently produced through the accumulation of smaller objects near the peaks of unstable density waves.

View original: http://arxiv.org/abs/1301.2064