Analysis of Numerical Algorithms for Computing Rapid Momentum Transfers between the Gas and Dust in Simulations of Circumstellar Disks

Stoyanovskaya, Olga P.; Vorobyov, Eduard I.; Снытников, В. Н.

doi:10.1134/s1063772918060069

Cited by 34 publications

(35 citation statements)

References 54 publications

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“…We studied numerically the global evolution of viscous and selfgravitating circumstellar disks starting from disk formation and ending after about one million years of disk evolution. Such long integration times were made possible thanks to the use of the numerical hydrodynamics code FEOSAD, originally developed by and modified in this work to include the effect of back-reaction of dust on gas according to the method laid out in Stoyanovskaya et al (2018). The turbulent viscosity in the disk is parameterized by a spatially and temporarily constant value of the Shakura-Sunyaev α-parameter, set equal to 0.01, which corresponds to the active MRI through the disk extent.…”

Section: Discussionmentioning

confidence: 99%

Gravitoviscous protoplanetary disks with a dust component

Vorobyov

Skliarevskii

Elbakyan

et al. 2019

A&A

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Aims. The central region of a circumstellar disk is difficult to resolve in global numerical simulations of collapsing cloud cores, but its effect on the evolution of the entire disk can be significant. Methods. We used numerical hydrodynamics simulations to model the long-term evolution of self-gravitating and viscous circumstellar disks in the thin-disk limit. Simulations start from the gravitational collapse of pre-stellar cores of 0.5–1.0 M⊙ and both gaseous and dusty subsystems were considered, including a model for dust growth. The inner unresolved 1.0 au of the disk is replaced with a central smart cell (CSC), a simplified model that simulates physical processes that may occur in this region. Results. We found that the mass transport rate through the CSC has an appreciable effect on the evolution of the entire disk. Models with slow mass transport form more massive and warmer disks, and are more susceptible to gravitational instability and fragmentation, including a newly identified episodic mode of disk fragmentation in the T Tauri phase of disk evolution. Models with slow mass transport through the CSC feature episodic accretion and luminosity bursts in the early evolution, while models with fast transport are characterized by a steadily declining accretion rate with low-amplitude flickering. Dust grows to a larger, decimeter size in the slow transport models and efficiently drifts in the CSC, where it accumulates and reaches the limit where a streaming instability becomes operational. We argue that gravitational instability, together with a streaming instability likely operating in the inner disk regions, constitute two concurrent planet-forming mechanisms, which may explain the observed diversity of exoplanetary orbits. Conclusions. We conclude that sophisticated models of the inner unresolved disk regions should be used when modeling the formation and evolution of gaseous and dusty protoplanetary disks.

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Section: Discussionmentioning

confidence: 99%

Gravitoviscous protoplanetary disks with a dust component

Vorobyov

Skliarevskii

Elbakyan

et al. 2019

A&A

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“…where the subscripts p and p refer to the planar components (r, φ) in polar coordinates; Σ g is the gas surface density; e is the internal energy per surface area; P is the vertically integrated gas pressure calculated via the ideal equation of state as P = (γ − 1)e with γ = 7/5; u p = v rr + v φφ is the gas velocity in the disk plane; and ∇ p =r∂/∂r +φr −1 ∂/∂φ is the gradient along the planar coordinates of the disk. The term f p is the drag force per unit mass between dust and gas, describing the back-reaction of dust on gas according to the method described in Stoyanovskaya et al (2018). The gravitational acceleration in the disk plane, g p = g rr + g φφ , takes into account self-gravity of the gaseous and dusty disk components found by solving the Poisson integral (see details in Vorobyov & Basu 2010) and the gravity of the central protostar when formed.…”

Section: Numerical Modelmentioning

confidence: 99%

Gravitoviscous protoplanetary disks with a dust component

Elbakyan

Johansen²,

Lambrechts³

et al. 2020

A&A

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Aims. We study the dynamics and growth of dust particles in circumstellar disks of different masses that are prone to gravitational instability during the critical first Myr of their evolution. Methods. We solved the hydrodynamics equations for a self-gravitating and viscous circumstellar disk in a thin-disk limit using the FEOSAD numerical hydrodynamics code. The dust component is made up of two different components: micron-sized dust and grown dust of evolving size. For the dust component, we considered the dust coagulation, fragmentation, momentum exchange with the gas, and dust self-gravity. Results. We found that the micron-sized dust particles grow rapidly in the circumstellar disk, reaching a few cm in size in the inner 100 au of the disk during less than 100 kyr after the disk formation, provided that fragmentation velocity is 30 ms−1. Due to the accretion of micron dust particles from the surrounding envelope, which serves as a micron dust reservoir, the approximately cm-sized dust particles continue to be present in the disk for more than 900 kyr after the disk formation and maintain a dust-to-gas ratio close to 0.01. We show that a strong correlation exists between the gas and pebble fluxes in the disk. We find that radial surface density distribution of pebbles in the disk shows power-law distribution with an index similar to that of the Minimum-mass solar nebula regardless the disk mass. We also show that the gas surface density in our models agrees well with measurements of dust in protoplanetary disks of AS 209, HD 163296, and DoAr 25 systems. Conclusions. Pebbles are formed during the very early stages of protoplanetary disk evolution. They play a crucial role in the planet formation process. Our disc simulations reveal the early onset (<105 yr) of an inwards-drifting flux of pebble-sized particles that makes up approximately between one hundredth and one tenth of the gas mass flux, which appears consistent with mm-observations of discs. Such a pebble flux would allow for the formation of planetesimals by streaming instability and the early growth of embryos by pebble accretion. We conclude that unlike the more common studies of isolated steady-state protoplanetary disks, more sophisticated global numerical simulations of circumstellar disk formation and evolution, including the pebble formation from the micron dust particles, are needed for performing realistic planet formation studies.

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“…They also require extremely high spatial resolu-tion in order to capture correctly the dephasing between gas and dust, i.e., the dissipation of energy through the drag . Some efficient bifluid treatments were developed to cope with these issues (e.g., semi implicit methods, Lorén-Aguilar & Bate 2014Bate , 2015Stoyanovskaya et al 2017Stoyanovskaya et al , 2018. As an alternative way to model correctly these mixtures, Laibe & Price (2014a) proposed an algorithm for smoothed Particle Hydrodynamic codes (SPH, Lucy 1977;Gingold & Monaghan 1977) using a monofluid formalism.…”

Section: Introductionmentioning

confidence: 99%

Small dust grain dynamics on adaptive mesh refinement grids

Lebreuilly

Commerçon

Laibe

2019

A&A

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Context. Small dust grains are essential ingredients of star, disk and planet formation. Aims. We present an Eulerian numerical approach to study small dust grain dynamics in the context of star and protoplanetary disk formation. It is designed for finite volume codes. We use it to investigate dust dynamics during the protostellar collapse. Methods. We present a method to solve the monofluid equations of gas and dust mixtures with several dust species in the diffusion approximation implemented in the adaptive-mesh-refinement code RAMSES. It uses a finite volume second-order Godunov method with a predictor-corrector MUSCL scheme to estimate the fluxes between the grid cells. Results. We benchmark our method against six distinct tests, dustyadvect, dustydiffuse, dustyshock, dustywave, settling and dustycollapse. We show that the scheme is second-order accurate in space on uniform grids and intermediate between second-and firstorder on non-uniform grids. We apply our method on various dustycollapse simulations of 1M cores composed of gas and dust. Conclusions. We developed an efficient approach to treat gas and dust dynamics in the diffusion regime on grid-based codes. The canonical tests were successfully passed. In the context of protostellar collapse, we show that dust is less coupled to the gas in the outer regions of the collapse where grains larger than 100 µm fall significantly faster than the gas.

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Analysis of Numerical Algorithms for Computing Rapid Momentum Transfers between the Gas and Dust in Simulations of Circumstellar Disks

Cited by 34 publications

References 54 publications

Gravitoviscous protoplanetary disks with a dust component

Gravitoviscous protoplanetary disks with a dust component

Gravitoviscous protoplanetary disks with a dust component

Small dust grain dynamics on adaptive mesh refinement grids

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