Empirical constraints on turbulence in proto-planetary discs

Rosotti, Giovanni

doi:10.1016/j.newar.2023.101674

Cited by 38 publications

(9 citation statements)

References 123 publications

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“…Since the MRI can only be directly studied in focused high-resolution magnetohydrodynamics simulations (e.g., Bai 2013), we use a parametric approach and set α = 0.001 as a constant of space and time. This value is also consistent with observations (see Rosotti 2023). We note, however, that the MRI may be fully suppressed with α ≤ 10 −4 (Bai 2013;Dullemond et al 2022) and this may have important consequences for dust dynamics and growth (Vorobyov et al 2018).…”

Section: Dust Growth Modelsupporting

confidence: 91%

Dust growth and pebble formation in the initial stages of protoplanetary disk evolution

Vorobyov,

Kulikov,

Elbakyan

et al. 2024

A&A

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The initial stages of planet formation may start concurrently with the formation of a gas-dust protoplanetary disk. This makes the study of the earliest stages of protoplanetary disk formation crucially important. Here we focus on dust growth and pebble formation in a protoplanetary disk that is still accreting from a parental cloud core. We have developed an original three-dimensional numerical hydrodynamics code, which computes the collapse of rotating clouds and disk formation on nested meshes using a novel hybrid Coarray Fortran-OpenMP approach for distributed and shared memory parallelization. Dust dynamics and growth are also included in the simulations. We found that the dust growth from $ to 1--10 mm already occurs in the initial few thousand years of disk evolution but the Stokes number hardly exceeds 0.1 because of higher disk densities and temperatures compared to the minimum mass Solar nebular. The ratio of the dust-to-gas vertical scale heights remains rather modest, 0.2--0.5, which may be explained by the perturbing action of spiral arms that develop in the disk soon after its formation. The dust-to-gas mass ratio in the disk midplane is highly nonhomogeneous throughout the disk extent and is in general enhanced by a factor of several compared to the fiducial 1:100 value. Low $ St $ hinders strong dust accumulation in the spiral arms compared to the rest of the disk and the nonsteady nature of the spirals is also an obstacle. The spatial distribution of pebbles in the disk midplane exhibits a highly nonhomogeneous and patchy character. The total mass of pebbles in the disk increases with time and reaches a few tens of Earth masses after a few tens of thousand years of disk evolution. We found that protoplanetary disks with an age $ 20$ kyr can possess notable amounts of pebbles and feature dust-to-gas density enhancements in the disk midplane. Hence, these young disks can already be ripe for the planet formation process to start. Multidimensional numerical models of disk formation that consider the coevolution of gas and dust including dust growth are important to improve our understanding of planet formation.

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Section: Dust Growth Modelsupporting

confidence: 91%

Dust growth and pebble formation in the initial stages of protoplanetary disk evolution

Vorobyov,

Kulikov,

Elbakyan

et al. 2024

A&A

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“…The gaseous component of protoplanetary disks has traditionally been described as undergoing viscous accretion (Lynden-Bell & Pringle 1974;Pringle 1981). In recent years, however, growing observational evidence is challenging this picture, as the low levels of turbulence detected in protoplanetary disks appear incompatible with the observed evolution (Pinte et al 2016;Flaherty et al 2018;Rosotti 2023). The best alternative to the classic viscous scenario is currently provided by MHD disk winds, originally proposed by Blandford & Payne (1982).…”

Section: Introductionmentioning

confidence: 99%

The Time Evolution of Md/Ṁ in Protoplanetary Disks as a Way to Disentangle between Viscosity and MHD Winds

Somigliana,

Testi,

Rosotti

et al. 2023

ApJL

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As the classic viscous paradigm for protoplanetary disk accretion is challenged by the observational evidence of low turbulence, the alternative scenario of MHD disk winds is being explored as being potentially able to reproduce the same observed features traditionally explained with viscosity. Although the two models lead to different disk properties, none of them has been ruled out by observations—mainly due to instrumental limitations. In this work, we present a viable method to distinguish between the viscous and MHD framework based on the different evolution of the distribution in the disk mass (M d )–accretion rate ( M ̇ ) plane of a disk population. With a synergy of analytical calculations and 1D numerical simulations, performed with the population synthesis code Diskpop, we find that both mechanisms predict the spread of the observed ratio M d / M ̇ in a disk population to decrease over time; however, this effect is much less pronounced in MHD-dominated populations compared with purely viscous populations. Furthermore, we demonstrate that this difference is detectable with the current observational facilities: we show that convolving the intrinsic spread with the observational uncertainties does not affect our result, as the observed spread in the MHD case remains significantly larger than in the viscous scenario. While the most recent data available show a better agreement with the wind model, ongoing and future efforts to obtain direct gas mass measurements with Atacama Large Millimeter/submillimeter Array and next-generation Very Large Array will cause a reassessment of this comparison in the near future.

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“…In general, if most disks are truly less turbulent than previously thought, as recent observations suggest (Pinte et al 2016;Flaherty et al 2020;Rosotti 2023), then irrespective of v f , our simulations suggest that the inner disk will experience an intense but short- lived episode of vapor enrichment, with the presence and location of the gap determining the intensity of the enrichment episode. On the other hand, disks with high turbulent α, irrespective of v f , may not see any enrichment in vapor in the inner regions.…”

Section: Fragmentation Velocity Versus Turbulent Viscositymentioning

confidence: 46%

The Effect of Dust Evolution and Traps on Inner Disk Water Enrichment

Kalyaan,

Pinilla,

Krijt

et al. 2023

ApJ

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Substructures in protoplanetary disks can act as dust traps that shape the radial distribution of pebbles. By blocking the passage of pebbles, the presence of gaps in disks may have a profound effect on pebble delivery into the inner disk, crucial for the formation of inner planets via pebble accretion. This process can also affect the delivery of volatiles (such as H2O) and their abundance within the water snow line region (within a few au). In this study, we aim to understand what effect the presence of gaps in the outer gas disk may have on water vapor enrichment in the inner disk. Building on previous work, we employ a volatile-inclusive disk evolution model that considers an evolving ice-bearing drifting dust population, sensitive to dust traps, which loses its icy content to sublimation upon reaching the snow line. We find that the vapor abundance in the inner disk is strongly affected by the fragmentation velocity (v f) and turbulence, which control how intense vapor enrichment from pebble delivery is, if present, and how long it may last. Generally, for disks with low to moderate turbulence (α ≤ 1 × 10−3) and a range of v f, radial locations and gap depths (especially those of the innermost gaps) can significantly alter enrichment. Shallow inner gaps may continuously leak material from beyond it, despite the presence of additional deep outer gaps. We finally find that for realistic v f (≤10 m s−1), the presence of gaps is more important than planetesimal formation beyond the snow line in regulating pebble and volatile delivery into the inner disk.

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Empirical constraints on turbulence in proto-planetary discs

Cited by 38 publications

References 123 publications

Dust growth and pebble formation in the initial stages of protoplanetary disk evolution

Dust growth and pebble formation in the initial stages of protoplanetary disk evolution

The Time Evolution of Md/Ṁ in Protoplanetary Disks as a Way to Disentangle between Viscosity and MHD Winds

The Effect of Dust Evolution and Traps on Inner Disk Water Enrichment

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