On dust-gas gravitational instabilities in protoplanetary discs

Abstract

In protoplanetary disks the aerodynamical friction between particles and gas induces a variety of instabilities that facilitate planet formation. Of these we examine the so-called `secular gravitational instability' (SGI) in the two-fluid approximation, deriving analytical expressions for its stability criteria and growth rates. Concurrently, we present a physical explanation of the instability that shows how it manifests upon an intermediate range of lengthscales exhibiting geostrophic balance in the gas component. In contrast to a single-fluid treatment, the SGI is quenched within a critical disk radius, as large as 10 AU and 30 AU for cm and mm sized particles respectively, although establishing robust estimates is hampered by uncertainties in the parameters (especially the strength of turbulence) and deficiencies in the razor-thin disk model we employ. It is unlikely, however, that the SGI is relevant for well-coupled dust. We conclude by applying these results to the question of planetesimal formation and the provenance of large-scale dust rings.

arXiv commentMNRAS accepted. 14 pages, 6 figures

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Cited by in corpus (15)

• A thermodynamic view of dusty protoplanetary disks
• Revised description of dust diffusion and a new instability creating multiple rings in protoplanetary disks
• Non-linear Development of Secular Gravitational Instability in Protoplanetary Disks
• Coagulation Instability in Protoplanetary Disks: A Novel Mechanism Connecting Collisional Growth and Hydrodynamical Clumping of Dust Particles
• Vortex instabilities triggered by low-mass planets in pebble-rich, inviscid protoplanetary discs
• On the non-axisymmetric fragmentation of rings generated by the Secular Gravitational Instability
• Axisymmetric simulations of the convective overstability in protoplanetary discs
• Streaming instabilities in accreting and magnetized laminar protoplanetary disks
• The detection of dust gap-ring structure in the outer region of the CR Cha protoplanetary disk
• Filling in the Gaps: Can Gravitationally Unstable Discs Form the Seeds of Gas Giant Planets?
• Dynamics of Porous Dust Aggregates and Gravitational Instability of Their Disk
• Nonlinear Outcome of Coagulation Instability in Protoplanetary Disks II: Dust Ring Formation Mediated by Backreaction and Fragmentation
• On Secular Gravitational Instability in Vertically Stratified Disks
• Dynamic role of dust in formation of molecular clouds
• Linear Analysis of the Nonaxisymmetric Secular Gravitational Instability