Dynamics of dusty vortices – I. Extensions and limitations of the terminal velocity approximation

Lovascio, Francesco; Paardekooper, Sijme-Jan

doi:10.1093/mnras/stz2035

Cited by 18 publications

(18 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…http://www.astro.uni-jena.de/Laboratory/Database/databases.html 4 Although we had also found two-peak signatures in the m = 1 phase inHammer et al (2019), those signatures were influenced by our use of the terminal velocity approximation, which breaks down near spiral shocks(Lovascio & Paardekooper 2019). Nonetheless, we find that same signature in this study without the use of that approximation.© 2016 RAS, MNRAS 000, 1-?…”

supporting

confidence: 57%

Which planets trigger longer-lived vortices: low-mass or high-mass?

Hammer,

Lin,

Kratter

et al. 2021

Preprint

View full text Add to dashboard Cite

Recent ALMA observations have found many protoplanetary discs with rings that can be explained by gap-opening planets less massive than Jupiter. Meanwhile, recent studies have suggested that protoplanetary discs should have low levels of turbulence. Past computational work on low-viscosity discs has hinted that these two developments might not be self-consistent because even low-mass planets can be accompanied by vortices instead of conventional double rings. We investigate this potential discrepancy by conducting hydrodynamic simulations of growing planetary cores in discs with various aspect ratios (H/r = 0.04, 0.06, 0.08) and viscosities (1.5 × 10 −5 α 3 × 10 −4 ), having these cores accrete their gas mass directly from the disc. With α < 10 −4 , we find that sub-Saturn-mass planets in discs with H/r 0.06 are more likely to be accompanied by dust asymmetries compared to Jupiter-mass planets because they can trigger several generations of vortices in succession. We also find that vortices with H/r = 0.08 survive > 6000 planet orbits regardless of the planet mass or disc mass because they are less affected by the planet's spiral waves. We connect our results to observations and find that the outward migration of vortices with H/r 0.08 may be able to explain the cavity in Oph IRS 48 or the two clumps in MWC 758. Lastly, we show that the lack of observed asymmetries in the disc population in Taurus is unexpected given the long asymmetry lifetimes in our low viscosity simulations (α ∼ 2 × 10 −5 ), a discrepancy we suggest is due to these discs having higher viscosities.

show abstract

supporting

confidence: 57%

Which planets trigger longer-lived vortices: low-mass or high-mass?

Hammer,

Lin,

Kratter

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…The terminal velocity approximation is unrealistic in low density regions or in shocked regions where the pressure is discontinuous (Lovascio & Paardekooper 2019). We cap the differential velocities to w cap in our models to avoid prohibitively small timesteps and unrealistically large variations in the dust ratio in strong shock fronts.…”

Section: Regularization Of the Differential Velocity And Dust Densitymentioning

confidence: 99%

Protostellar collapse: the conditions to form dust-rich protoplanetary disks

Lebreuilly

Commerçon

Laibe

2020

A&A

View full text Add to dashboard Cite

Context. Dust plays a key role during star, disk and planet formation. Yet, its dynamics during the protostellar collapse remains a poorly investigated field. Recent studies seem to indicate that dust may decouple efficiently from the gas during these early stages. Aims. We aim to understand how much and in which regions dust grains concentrate during the early phases of the protostellar collapse, and see how it depends on the properties of the initial cloud and of the solid particles. Methods. We use the multiple species dust dynamics solver multigrain of the grid-based code RAMSES to perform various simulations of dusty collapses. We perform hydrodynamical and magnetohydrodynamical simulations where we vary the maximum size of the dust distribution, the thermal-to-gravitational energy ratio and the magnetic properties of the cloud. We simulate the simultaneous evolution of ten neutral dust grains species with grain sizes varying from a few nanometers to a few hundredth of microns. Results. We obtain a significant decoupling between the gas and the dust for grains of typical sizes a few ∼ 10 µm. This decoupling strongly depends on the thermal-to-gravitational energy ratio, the grain sizes or the inclusion of a magnetic field. With a semi-analytic model calibrated on our results, we show that the dust ratio mostly varies exponentially with the initial Stokes number at a rate that depends on the local cloud properties. Conclusions. We find that larger grains tend to settle and drift efficiently in the first-core and in the newly formed disk. This can produce dust-togas ratios of several times the initial value. Dust concentrates in high density regions (cores, disk and pseudo-disk) and is depleted in low density regions (envelope and outflows). The size at which grains decouple from the gas depends on the initial properties of the clouds. Since dust can not necessarily be used as a proxy for gas during the collapse, we emphasize on the necessity of including the treatment of its dynamics in protostellar collapse simulations.

show abstract

“…Thus, it appears that the overall impact of dust in the system is stronger in the latter study. One reason might be that the single fluid de-scription implicitly assumes the terminal velocity approximation (Youdin and Goodman 2005;Lovascio and Paardekooper 2019) for the dust. Furthermore, the different numerical setup used in Lin ( 2019) is possibly more dissipative such that the overall level of turbulence is expected to be slightly weaker.…”

Section: Dust Settling In the Absence Of A Pressure Bumpmentioning

confidence: 99%

Impact of Local Pressure Enhancements on Dust Concentration inTurbulent Protoplanetary Discs

Lehmann,

Lin

2021

Preprint

View full text Add to dashboard Cite

The standard core accretion model for planetesimal formation in protoplanetary discs (PPDs) is known to bear a number of challenges. One is the vertical settling of dust to the disc mid-plane against turbulent stirring. This is particularly relevant in presence of the vertical shear instability (VSI), a purely hydrodynamic instability applicable to the outer parts of PPDs, which drives moderate turbulence characterized by large-scale vertical motions. We investigate the evolution of dust and gas in the vicinity of local pressure enhancements (pressure bumps) in a PPD with turbulence sustained by the VSI. Our goal is to determine the morphology of dust concentrations and if dust can concentrate sufficiently to reach conditions that can trigger the Streaming Instability (SI). We perform a suite of global 2D axisymmetric and 3D simulations of dust and gas for a range of values for Σ d /Σ g (ratio of dust-to-gas surface mass densities or metallicity), particle Stokes numbers τ, and pressure bump amplitude A. Dust feedback onto the gas is included. For the first time we demonstrate in global 3D simulations the collection of dust in long-lived vortices induced by the VSI. These vortices, which undergo slow radial inward drift, are the dusty analogs of large long-lived vortices found in previous dust-free simulations of the VSI. Without a pressure bump and for solar metallicity Z ≈ 0.01 and Stokes numbers τ ∼ 10 −2 we find that such vortices can reach dust-to-gas density ratios slightly below unity in the discs' mid-plane, while for Z 0.05 long-lived vortices are largely absent. In the presence of a pressure bump, for Z ≈ 0.01 and τ ∼ 10 −2 a dusty vortex forms that reaches dust-to-gas ratios of a few times unity, such that the SI is expected to develop, before it eventually shears out into a turbulent dust ring. At intermediate metallicities Z ∼ 0.03 this occurs for τ ∼ 5 • 10 −3 , but with a weaker and more short-lived vortex, while for larger τ only a turbulent dust ring forms. For Z 0.03 we find that the dust ring becomes increasingly axisymmetric for increasing τ and dust-to-gas ratios reach order unity for τ 5 • 10 −3 . Furthermore, the vertical mass flow profile of the disc is strongly affected by dust for Z 0.03, such that gas is transported inward near the mid-plane and outward at larger heights, which is the reversed situation compared to simulations with zero or small amounts of dust. We find Reynolds stresses or α-values to drop moderately as ∼ 10 −3 − 10 −4 for metallicities increasing as Z = 0 − 0.05. Our results suggest that the VSI can play an active role in the formation of planetesimals through the formation of vortices for plausible values of metallicity and particle size. Also it may provide a natural explanation for the presence or absence of asymmetries of observed dust rings in PPDs, depending on the background metallicity.

show abstract

Dynamics of dusty vortices – I. Extensions and limitations of the terminal velocity approximation

Cited by 18 publications

References 44 publications

Which planets trigger longer-lived vortices: low-mass or high-mass?

Which planets trigger longer-lived vortices: low-mass or high-mass?

Protostellar collapse: the conditions to form dust-rich protoplanetary disks

Impact of Local Pressure Enhancements on Dust Concentration inTurbulent Protoplanetary Discs

Contact Info

Product

Resources

About