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Dust dynamics and vertical settling in gravitoturbulent protoplanetary discs
- Source :
- Monthly Notices of the Royal Astronomical Society
- Publication Year :
- 2020
- Publisher :
- arXiv, 2020.
-
Abstract
- Gravitational instability (GI) controls the dynamics of young massive protoplanetary discs. Apart from facilitating gas accretion on to the central protostar, it must also impact on the process of planet formation: directly through fragmentation, and indirectly through the turbulent concentration of small solids. To understand the latter process, it is essential to determine the dust dynamics in such a turbulent flow. For that purpose, we conduct a series of 3D shearing box simulations of coupled gas and dust, including the gas's self-gravity and scanning a range of Stokes numbers, from 0.001 to ~0.2. First, we show that the vertical settling of dust in the midplane is significantly impeded by gravitoturbulence, with the dust scale-height roughly 0.6 times the gas scale height for centimetre grains. This is a result of the strong vertical diffusion issuing from (a) small-scale inertial-wave turbulence feeding off the GI spiral waves and (b) the larger-scale vertical circulations that naturally accompany the spirals. Second, we show that at R=50 AU concentration events involving sub-metre particles and yielding order 1 dust to gas ratios are rare and last for less than an orbit. Moreover, dust concentration is less efficient in 3D than in 2D simulations. We conclude that GI is not especially prone to the turbulent accumulation of dust grains. Finally, the large dust scale-height measured in simulations could be, in the future, compared with that of edge-on discs seen by ALMA, thus aiding detection and characterisation of GI in real systems.<br />Comment: Accepted in MNRAS, 13 pages
- Subjects :
- Gravitational instability
FOS: Physical sciences
5109 Space Sciences
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
01 natural sciences
Settling
Planet
0103 physical sciences
Protostar
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
Solar and Stellar Astrophysics (astro-ph.SR)
Shearing (physics)
Physics
Earth and Planetary Astrophysics (astro-ph.EP)
010308 nuclear & particles physics
Turbulence
Real systems
Astronomy and Astrophysics
Scale height
Astrophysics - Solar and Stellar Astrophysics
13. Climate action
Space and Planetary Science
Astrophysics::Earth and Planetary Astrophysics
51 Physical Sciences
Astrophysics - Earth and Planetary Astrophysics
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Accession number :
- edsair.doi.dedup.....a68e4a2b4650067bd03a6ff16e6a0b10
- Full Text :
- https://doi.org/10.48550/arxiv.2003.01167