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Abstract The filamentary nature of accretion streams found around embedded sources suggests that protostellar disks experience heterogenous infall from the star-forming environment, consistent with the accretion behavior onto star-forming cores in top-down star-cluster formation simulations. This may produce disk substructures in the form of rings, gaps, and spirals that continue to be identified by high-resolution imaging surveys in both embedded Class 0/I and later Class II sources. We present a parameter study of anisotropic infall, informed by the properties of accretion flows onto protostellar cores in numerical simulations, and varying the relative specific angular momentum of incoming flows as well as their flow geometry. Our results show that anisotropic infall perturbs the disk and readily launches the Rossby wave instability. It forms vortices at the inner and outer edges of the infall zone where material is deposited. These vortices drive spiral waves and angular momentum transport, with some models able to drive stresses corresponding to a viscosity parameter on the order ofα∼ 10−2. The resulting azimuthal shear forms robust pressure bumps that act as barriers to radial drift of dust grains, as demonstrated by postprocessing calculations of drift-dominated dust evolution. We discuss how a self-consistent model of anisotropic infall can account for the formation of millimeter rings in the outer disk as well as producing compact dust disks, consistent with observations of embedded sources.
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This content will become publicly available on December 1, 2025
A High-resolution Simulation of Protoplanetary Disk Turbulence Driven by the Vertical Shear Instability
Abstract A high-resolution fourth-order Padé scheme is used to simulate locally isothermal 3D disk turbulence driven by the vertical shear instability (VSI) using 268.4 M points. In the early nonlinear period of axisymmetric VSI, angular momentum transport by vertical jets creates correlatedN-shaped radial profiles of perturbation vertical and azimuthal velocity. This implies dominance of positive perturbation vertical vorticity layers and a recently discovered angular momentum staircase with respect to radius (r). These features are present in 3D in a weaker form. The 3D flow consists of vertically and azimuthally coherent turbulent shear layers containing small vortices with all three vorticity components active. Previously observed large persistent vortices in the interior of the domain driven by the Rossby wave instability are absent. We speculate that this is due to a weaker angular momentum staircase in 3D in the present simulations compared to a previous simulation. The turbulent viscosity parameterα(r) increases linearly withr. At intermediate resolution, the value ofα(r) at midradius is close to that of a previous simulation. The specific kinetic energy spectrum with respect to radial wavenumber has a power-law region with exponent −1.84, close to the value −2 expected for shear layers. The spectrum with respect to azimuthal wavenumber has a −5/3 region and lacks a −5 region reported in an earlier study. Finally, it is found that axisymmetric VSI has artifacts at late times, including a very strong angular momentum staircase, which in 3D is present weakly in the disk’s upper layers.
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- Award ID(s):
- 2007422
- PAR ID:
- 10621841
- Publisher / Repository:
- American Astronomical Society
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 977
- Issue:
- 2
- ISSN:
- 0004-637X
- Page Range / eLocation ID:
- 272
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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