Related papers: Secular Instability and Planetesimal Formation in …
The behaviour of sedimenting particles depends on the dust-to-gas ratio of the fluid. Linear stability analysis shows that solids settling in the Epstein drag regime would remain homogeneously distributed in non-rotating incompressible…
The discovery that axisymmetric dust rings are ubiquitous in protoplanetary disks has provoked a flurry of research on the role of pressure bumps in planet formation. High-resolution simulations by our group have shown that even a modest…
Gravitational instability (GI) of a dust-rich layer at the midplane of a gaseous circumstellar disk is one proposed mechanism to form planetesimals, the building blocks of rocky planets and gas giant cores. Self-gravity competes against the…
The early stages of planet formation are still not well understood. Coagulation models have revealed numerous obstacles to the dust growth, such as the bouncing, fragmentation and radial drift barriers. We study the interplay between dust…
Dust concentration in protoplanetary disks (PPDs) is the first step towards planetesimal formation, a crucial yet highly uncertain stage in planet formation. Although the streaming instability (SI) is widely recognized as a powerful…
Previous work on protoplanetary dust growth shows halt at centimeter sizes owing to the occurrence of bouncing at velocities of $\geq$ 0.1 $ms^{-1}$ and fragmentation at velocities $\geq$ 1 $ms^{-1}$. To overcome these barriers, spatial…
Planet formation via core accretion involves the growth of solids that can accumulate to form planetary cores. There are a number of barriers to the collisional growth of solids in protostellar discs, one of which is the drift, or metre,…
Clumping by streaming instability (SI) leading to gravitational collapse is the leading proposed mechanism for forming planetesimals, the building blocks of terrestrial planets and giant-planet cores. The critical dust-to-gas density ratio…
In order to circumvent the loss of solid material through radial drift towards the central star, the trapping of dust inside persistent vortices in protoplanetary discs has often been suggested as a process that can eventually lead to…
Debris rings of dust are found around young luminous stars such as HR4796A and HD141569. Some of these entities have sharp edges and gaps which have been interpreted as evidence for the presence of shepherding and embedded planets. Here we…
The level of dust vertical settling and radial dust concentration in disks is of critical importance for understanding the efficiency of planet formation. We present the first uniform analysis of the vertical extent of millimeter dust for a…
The streaming instability is a promising mechanism for planetesimal formation. The instability can rapidly form dense clumps that collapse self-gravitationally, which is efficient for large dust grains with the Stokes number on the order of…
We have conducted the first comprehensive numerical investigation of the relative velocity distribution of dust particles in self-gravitating protoplanetary discs with a view to assessing the viability of planetesimal formation via direct…
In protoplanetary disks, the formation of planetesimals via streaming and/or gravitational instabilities requires regions with a locally enhanced dust-to-gas mass ratio. Conventionally, gas pressure maxima sustained by gas surface density…
Dust growth and settling considerably affect the spectral energy distributions (SEDs) of protoplanetary disks. We investigated dust growth and settling in protoplanetary disks through numerical simulations to examine time-evolution of the…
Dust particles sediment toward the midplanes of protoplanetary disks, forming dust-rich sublayers encased in gas. What densities must the particle sublayer attain before it can fragment by self-gravity? We describe various candidate…
We outline a novel linear instability that may arise in the dead-zones of protostellar disks, and possibly the fluid interiors of planets and protoplanets. In essence it is an axisymmetric buoyancy instability, but one that would not be…
Substellar atmospheres are observed to be irregularly variable for which the formation of dust clouds is the most promising candidate explanation. The atmospheric gas is convectively unstable and, last but not least, colliding convective…
The vertical shear instability (VSI) is a hydrodynamical instability that requires rapid gas cooling and has been suggested to operate in outer regions of protoplanetary disks. The VSI drives turbulence with strong vertical motions, which…
Aims. Dust plays a crucial role in the evolution of protoplanetary disks. We study the dynamics and growth of initially sub-$\mu m$ dust particles in self-gravitating young protoplanetary disks with various strengths of turbulent viscosity.…