Turbulent Mixing in the Outer Solar Nebula

Abstract

The effects of turbulence on the mixing of gases and dust in the outer Solar nebula are examined using 3-D MHD calculations in the shearing-box approximation with vertical stratification. The turbulence is driven by the magneto-rotational instability. The magnetic and hydrodynamic stresses in the turbulence correspond to an accretion time at the midplane about equal to the lifetimes of T Tauri disks, while accretion in the surface layers is thirty times faster. The mixing resulting from the turbulence is also fastest in the surface layers. The mixing rate is similar to the rate of radial exchange of orbital angular momentum, so that the Schmidt number is near unity. The vertical spreading of a trace species is well-matched by solutions of a damped wave equation when the flow is horizontally-averaged. The damped wave description can be used to inexpensively treat mixing in 1-D chemical models. However, even in calculations reaching a statistical steady state, the concentration at any given time varies substantially over horizontal planes, due to fluctuations in the rate and direction of the transport. In addition to mixing species that are formed under widely varying conditions, the turbulence intermittently forces the nebula away from local chemical equilibrium. The different transport rates in the surface layers and interior may affect estimates of the grain evolution and molecular abundances during the formation of the Solar system.

To appear in the Astrophysical Journal; 20 pages, 9 figures

References in corpus (24)

• Disk Frequencies and Lifetimes in Young Clusters
• Spectral Energy Distributions of T Tauri Stars With Passive Circumstellar Disks
• Dust coagulation in protoplanetary disks: a rapid depletion of small grains
• Accretion Disks Around Young Objects. III. Grain Growth
• The Formation and Structure of a Strongly Magnetized Corona above Weakly Magnetized Accretion Disks
• Magnetorotational Instability in Protoplanetary Disks. II. Ionization State and Unstable Regions
• Warm Molecular Layers in Protoplanetary Disks
• The conductivity of dense molecular gas
• Dust diffusion in protoplanetary discs by magnetorotational turbulence
• The Effect of the Hall Term on the Nonlinear Evolution of the Magnetorotational Instability: II. Saturation Level and Critical Magnetic Reynolds Number
• The Effect of the Hall Term on the Nonlinear Evolution of the Magnetorotational Instability: I. Local Axisymmetric Simulations
• Saturation and Thermalization of the Magnetorotational Instability: Recurrent Channel Flows and Reconnections
• Non-Fickian diffusion and tau approximation from numerical turbulence
• High-resolution Near-Infrared Images and Models of the Circumstellar Disk in HH 30
• Nonlinear Evolution of the Magnetorotational Instability in Ion-Neutral Disks
• Magnetorotational instability in protoplanetary discs
• On the Ionisation Fraction in Protoplanetary Disks II: The Effect of Turbulent Mixing on Gas--phase Chemistry
• Diffusion coefficient of a passive contaminant in a local MHD model of a turbulent accretion disc
• Deuterated H${}_3^{+}$ in proto-planetary disks
• A New Approach to Turbulent Transport of a Mean Scalar
• Ten-Micron Observations of Nearby Young Stars
• Early dust evolution in protostellar accretion disks
• The First Detection of Spatially Resolved Mid-Infrared Scattered Light from a Protoplanetary Disk
• Chaos in Turbulence Driven by the Magnetorotational Instability

Cited by in corpus (41)

• Particle Stirring in Turbulent Gas Disks: Including Orbital Oscillations
• Dynamics of Protoplanetary Disks
• Protoplanetary Disk Turbulence Driven by the Streaming Instability: Non-Linear Saturation and Particle Concentration
• A Three-Dimensional View of Turbulence: Constraints on Turbulent Motions in the HD 163296 Protoplanetary Disk using DCO${}^{+}$
• Magnetic fields in protoplanetary disks
• Dust dynamics during protoplanetary disc clearing
• Turbulent Mixing and the Dead Zone in Protostellar Disks
• Dust settling in local simulations of turbulent protoplanetary disks
• Magnetorotational Instability Driven Accretion in Protoplanetary Disks
• Global MHD simulations of stratified and turbulent protoplanetary discs. I. Model properties
• Local outflows from turbulent accretion disks
• Modeling Magnetorotational Turbulence in Protoplanetary Disks with Dead Zones
• Turbulence and Steady Flows in 3D Global Stratified MHD Simulations of Accretion Disks
• Hall diffusion and the magnetorotational instability in protoplanetary discs
• The Turbulent Magnetic Prandtl Number of MHD Turbulence in Disks
• Dust Transport in Protostellar Disks Through Turbulence and Settling
• Gas and dust dynamics in starlight-heated protoplanetary disks
• Planet Formation with Migration
• Midplane sedimentation of large solid bodies in turbulent protoplanetary discs
• The Inner Rim of YSO Disks: Effects of dust grain evolution
• Growth and migration of solids in evolving protostellar disks I: Methods and Analytical tests
• On the dynamics of planetesimals embedded in turbulent protoplanetary discs
• Turbulent diffusion in protoplanetary discs: the effect of an imposed magnetic field
• Electrostatic Barrier against Dust Growth in Protoplanetary Disks. II. Measuring the Size of the "Frozen" Zone
• Evolution of the Solar Nebula. VIII. Spatial and Temporal Heterogeneity of Short-Lived Radioisotopes and Stable Oxygen Isotopes
• Radial Transport of Large-Scale Magnetic Fields in Accretion Disks. I. Steady Solutions and an Upper Limit on the Vertical Field Strength
• From discs to planetesimals I: evolution of gas and dust discs
• The composition of the protosolar disk and the formation conditions for comets
• Population synthesis of exocometary gas around A stars
• The Fate of Planetesimals in Turbulent Disks with Dead Zones. I. The Turbulent Stirring Recipe
• The Saturation Limit of the Magnetorotational Instability
• Magnetorotational instability in protoplanetary discs: The effect of dust grains
• Induced Turbulence and the Density Structure of the Dust Layer in a Protoplanetary Disk
• Global Structure of Magnetorotationally Turbulent Protoplanetary Discs
• The role of magnetic fields for planetary formation
• Measuring Organic Molecular Emission in Disks with Low Resolution Spitzer Spectroscopy
• Spatial distribution of crystalline silicates in protoplanetary disks: How to interpret mid-infrared observations
• MRI-driven angular momentum transport in protoplanetary disks
• Self-Sustained Recycling in the Inner Dust Ring of Pre-Transitional Disks
• Formation of stars and planets: the role of magnetic fields
• Photophoretic Levitation and Trapping of Dust in the Inner Regions of Protoplanetary Disks