Volume 529, May 2011
|Number of page(s)||16|
|Section||Planets and planetary systems|
|Published online||01 April 2011|
High-resolution simulations of planetesimal formation in turbulent protoplanetary discs
Lund Observatory, Box 43, 221 00
2 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
Accepted: 2 March 2011
We present high-resolution computer simulations of dust dynamics and planetesimal formation in turbulence generated by the magnetorotational instability. We show that the turbulent viscosity associated with magnetorotational turbulence in a non-stratified shearing box increases when going from 2563 to 5123 grid points in the presence of a weak imposed magnetic field, yielding a turbulent viscosity of α ≈ 0.003 at high resolution. Particles representing approximately meter-sized boulders concentrate in large-scale high-pressure regions in the simulation box. The appearance of zonal flows and particle concentration in pressure bumps is relatively similar at moderate (2563) and high (5123) resolution. In the moderate-resolution simulation we activate particle self-gravity at a time when there is little particle concentration, in contrast with previous simulations where particle self-gravity was activated during a concentration event. We observe that bound clumps form over the next ten orbits, with initial birth masses of a few times the dwarf planet Ceres. At high resolution we activate self-gravity during a particle concentration event, leading to a burst of planetesimal formation, with clump masses ranging from a significant fraction of to several times the mass of Ceres. We present a new domain decomposition algorithm for particle-mesh schemes. Particles are spread evenly among the processors and the local gas velocity field and assigned drag forces are exchanged between a domain-decomposed mesh and discrete blocks of particles. We obtain good load balancing on up to 4096 cores even in simulations where particles sediment to the mid-plane and concentrate in pressure bumps.
Key words: accretion, accretion disks / methods: numerical / magnetohydrodynamics (MHD) / planets and satellites: formation / planetary systems / turbulence
© ESO, 2011
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