The coexistence of the streaming instability and the vertical shear instability in protoplanetary disks: Planetesimal formation thresholds explored in two-dimensional global models

Abstract

The streaming instability is a promising mechanism to induce the formation of planetesimals. Nonetheless, this process has been found in previous studies to require either a dust-to-gas surface density ratio or a dust size that is enhanced compared to observed values. Employing two-dimensional global simulations of protoplanetary disks, we show that the vertical shear instability and the streaming instability in concert can cause dust concentration that is sufficient for planetesimal formation for lower surface density ratios and smaller dust sizes than the streaming instability in isolation, and in particular under conditions that are consistent with observational constraints. This is because dust overdensities forming in pressure bumps induced by the vertical shear instability act as seeds for the streaming instability and are enhanced by it. While our two-dimensional model does not include self-gravity, we find that strong dust clumping and the formation (and dissolution) of gravitationally unstable overdensities can be robustly inferred from the evolution of the maximum or the mean dust-to-gas volume density ratio. The vertical shear instability puffs up the dust layer to an average mid-plane dust-to-gas density ratio that is significantly below unity. We therefore find that reaching a mid-plane density ratio of one is not necessary to trigger planetesimal formation via the streaming instability when it acts in unison with the vertical shear instability.

17 pages, 12 figures, 2 tables; accepted for publication in A&A; comments welcome

References in corpus (43)

• Planetesimal formation starts at the snow line
• How to form planetesimals from mm-sized chondrules and chondrule aggregates
• Close-in planetesimal formation by pile-up of drifting pebbles
• One Solution to the Mass Budget Problem for Planet Formation: Optically Thick Disks with Dust Scattering
• Lupus disks with faint CO isotopologues: low gas/dust or large carbon depletion?
• Initial mass function of planetesimals formed by the streaming instability
• The Radial Distribution of Dust Particles in the HL Tau Disk from ALMA and VLA Observations
• Thresholds for Particle Clumping by the Streaming Instability
• Survival of the mm-cm size grain population observed in protoplanetary disks
• Can dust coagulation trigger streaming instability?
• The evidence of radio polarization induced by the radiative grain alignment and self-scattering of dust grains in a protoplanetary disk
• Vertical shear instability in accretion disc models with radiation transport
• The anomalously low (sub)millimeter spectral indices of some protoplanetary disks may be explained by dust self-scattering
• An ALMA Survey of CO isotopologue emission from Protoplanetary Disks in Chamaeleon I
• Radiation Hydrodynamical Turbulence In Protoplanetary Disks: Numerical Models and Observational Constraints
• Characterizing the dust content of disk substructures in TW Hya
• Turbulence sets the length scale for planetesimal formation: Local 2D simulations of streaming instability and planetesimal formation
• Particle dynamics in discs with turbulence generated by the vertical shear instability
• Streaming Instability for Particle-Size Distributions
• Gas and dust dynamics in starlight-heated protoplanetary disks
• On the vertical-shear instability in astrophysical discs
• Planetesimal Population Synthesis: Pebble Flux Regulated Planetesimal Formation
• On the Feeding Zone of Planetesimal Formation by the Streaming Instability
• Dust settling against hydrodynamic turbulence in protoplanetary discs
• Linear growth of streaming instability in pressure bumps
• Radial variations in grain sizes and dust scale heights in the protoplanetary disk around HD 163296 revealed by ALMA polarization observation
• An analytical model of radial dust trapping in protoplanetary disks
• Streaming Instability with Multiple Dust Species: II. Turbulence and Dust-Gas Dynamics at Nonlinear Saturation
• Pebble trapping in vortices: three-dimensional simulations
• The Streaming Instability Cannot Form Planetesimals from mm-size Grains in Pressure Bumps
• Dust Settling and Clumping in MRI Turbulent Outer Protoplanetary Disks
• Solving grain size inconsistency between ALMA polarization and VLA continuum in the Ophiuchus IRS 48 protoplanetary disk
• Streaming instability of multiple particle species II -- Numerical convergence with increasing particle number
• New Constraints on Protoplanetary Disk Gas Masses in Lupus
• Self-scattering of non-spherical dust grains
• Impact of Local Pressure Enhancements on Dust Concentration inTurbulent Protoplanetary Discs
• Turbulent Dust-trapping Rings as Efficient Sites for Planetesimal Formation
• Resilience of Planetesimal Formation in Weakly-Reinforced Pressure Bumps
• Modeling of the ALMA HL Tau Polarization by Mixture of Grain Alignment and Self-scattering
• Streaming instabilities in accreting and magnetized laminar protoplanetary disks
• Streaming instability in a global patch simulation of protoplanetary disks
• Self-scattering on large, porous grains in protoplanetary disks with dust settling
• Exploring the Grain Properties in the Disk of HL Tau with an Evolutionary Model

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• Planetesimal formation via the streaming instability in simulations of infall dominated young disks
• Strong clumping in global streaming instability simulations with a dusty fluid
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• Exploring the conditions for forming planetesimals by the streaming instability and planetary systems by pebble accretion
• Streaming instabilities in accreting protoplanetary disks: A parameter study
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