Journal
ASTRONOMY & ASTROPHYSICS
Volume 594, Issue -, Pages -Publisher
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201527716
Keywords
instabilities; hydrodynamics; accretion, accretion disks; radiative transfer
Categories
Funding
- Landesgraduiertenforderung of the state of Baden-Wurttemberg
- German Research Foundation (DFG) [KL 650/16]
- DFG
- Ministry for Science, Research and Arts of the state Baden-Wurttemberg)
Ask authors/readers for more resources
Context. Among the candidates for generating turbulence in accretion discs in situations with low intrinsic ionization, the vertical shear instability (VSI) has become an interesting candidate, since it relies purely on a vertical gradient in the angular velocity. Existing numerical simulations have shown that alpha-values a few times 10(-4) can be generated. Aims. The particle growth in the early planet formation phase is determined by the dynamics of embedded dust particles. Here, we address, in particular, the efficiency of VSI-turbulence in concentrating particles to generate overdensities and low collision velocities. Methods. We perform three-dimensional (3D) numerical hydrodynamical simulations of accretion discs around young stars that include radiative transport and irradiation from the central star. The motion of embedded particles within a size range of a fraction of mm up to several m is followed using standard drag formula. Results. We confirm that, under realistic conditions, the VSI is able to generate turbulence in full 3D protoplanetary discs. The irradiated disc shows turbulence within 10 to 60 au. The mean radial motion of the gas is such that it is directed inward near the midplane and outward in the surface layers. We find that large particles drift inward with the expected speed, while small particles can experience phases of outward drift. Additionally, the particles show bunching behaviour with overdensities reaching five times the average value, which is strongest for dimensionless stopping times around unity. Conclusions. Particles in a VSI-turbulent discs are concentrated in large-scale turbulent eddies and show low relative speeds that allow for growing collisions. The reached overdensities will also enable the onset of streaming instabilities, further enhancing particle growth. The outward drift for small particles at higher disk elevations enable the transport of processed high temperature material in the solar system to greater distances.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available