2016/03/21 by Ji-Ming Shi, Zhaohuan Zhu, James M. Stone +1 · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astrophysics #Astrophysics and Star Formation Studies #Classical mechanics #Formation and evolution of the Solar System #Gravitational instability #Instability #Mechanics #Physics #Planet #Planetesimal #Stellar, planetary, and galactic studies #Streaming instability #Turbulence #astro-ph.EP
paper · pdf · doi:10.1093/mnras/stw692
MNRAS accepted
arxiv created 2016/03/21 · openalex publication_date 2016/03/28 · arxiv updated 2016/04/20 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The dynamics of solid bodies in protoplanetary discs are subject to the properties of any underlying gas turbulence. Turbulence driven by disc self-gravity shows features distinct from those driven by the magnetorotational instability (MRI). We study the dynamics of solids in gravito-turbulent discs with two-dimensional (in the disc plane), hybrid (particle and gas) simulations. Gravito-turbulent discs can exhibit stronger gravitational stirring than MRI-active discs, resulting in greater radial diffusion and larger eccentricities and relative speeds for large particles (those with dimensionless stopping times <it>t</it><inf>stop</inf>Ω > 1, where Ω is the orbital frequency). The agglomeration of large particles into planetesimals by pairwise collisions is therefore disfavoured in gravito-turbulent discs. However, the relative speeds of intermediate-size particles (<it>t</it><inf>stop</inf>Ω ∼ 1) are significantly reduced as such particles are collected by gas drag and gas gravity into coherent filament-like structures with densities high enough to trigger gravitational collapse. First-generation planetesimals may form via gravitational instability of dust in marginally gravitationally unstable gas discs.