Dust to planetesimals: Settling and coagulation in the solar nebula

Weidenschilling, S. J.

doi:10.1016/0019-1035(80)90064-0

Cited by 473 publications

(349 citation statements)

References 23 publications

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“…Models for the growth of bodies in the solar nebula (e.g. Weidenschilling, 1980Weidenschilling, , 1984Weidenschilling, , 1997Weidenschilling, , 2000Weidenschilling and Cuzzi, 1993;Dullemond and Dominik, 2005) have shown that a range of particle sizes would exist at a given location in the nebula. As will be discussed below, different sized objects will have very different dynamical behaviors in a viscous disk that must be taken into account.…”

Section: Previous Models Of Water Transport In the Solar Nebulamentioning

confidence: 99%

The evolution of the water distribution in a viscous protoplanetary disk

Ciesla

Cuzzi

2006

Icarus

314

356

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Astronomical observations have shown that protoplanetary disks are dynamic objects through which mass is transported and accreted by the central star. This transport causes the disks to decrease in mass and cool over time, and such evolution is expected to have occurred in our own solar nebula. Age dating of meteorite constituents shows that their creation, evolution, and accumulation occupied several Myr, and over this time disk properties would evolve significantly. Moreover, on this timescale, solid particles decouple from the gas in the disk and their evolution follows a different path. It is in this context that we must understand how our own solar nebula evolved and what effects this evolution had on the primitive materials contained within it. Here we present a model which tracks how the distribution of water changes in an evolving disk as the water-bearing species experience condensation, accretion, transport, collisional destruction, and vaporization. Because solids are transported in a disk at different rates depending on their sizes, the motions will lead to water being concentrated in some regions of a disk and depleted in others. These enhancements and depletions are consistent with the conditions needed to explain some aspects of the chemistry of chondritic meteorites and formation of giant planets. The levels of concentration and depletion, as well as their locations, depend strongly on the combined effects of the gaseous disk evolution, the formation of rapidly migrating rubble, and the growth of immobile planetesimals. Understanding how these processes operate simultaneously is critical to developing our models for meteorite parent body formation in the solar system and giant planet formation throughout the galaxy. We present examples of evolution under a range of plausible assumptions and demonstrate how the chemical evolution of the inner region of a protoplanetary disk is intimately connected to the physical processes which occur in the outer regions.

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Section: Previous Models Of Water Transport In the Solar Nebulamentioning

confidence: 99%

The evolution of the water distribution in a viscous protoplanetary disk

Ciesla

Cuzzi

2006

Icarus

314

356

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“…Then the chondrules also had to be brought together swiftly into much larger aggregations, in order to survive in orbit and not be swept into the Sun along with the disk gases. Traditionally, clumping of dust into aggregates and gravitational settling of the aggregates to the midplane of the nebula have been invoked to assist in the buildup of dust into planetesimals (e.g., Weidenschilling, 1980). However, because the component of solar gravity normal to the disk midplane at the present asteroid belt was very feeble, and dust aggregates would be very weak, long times and a placid nebular environment would be required to accomplish this (if it can be accomplished at all).…”

Section: Spiral Arms and The Aggregation Of Chondrite Componentsmentioning

confidence: 99%

Processing of chondritic and planetary material in spiral density waves in the nebula

Wood

1996

Meteorit & Planetary Scien

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Abstract-A widely held view of nebular evolution is that during the -0.5 Ma while interstellar material was collapsing onto the disk, the latter grew in mass to the point of gravitational instability. It responded to this by losing axial symmetry, growing spiral arms that had the capacity to tidally redistribute disk mass (inward) and angular momentum (outward) and prevent further increase in the disWprotosun mass ratio. The spiral arms (density waves) rotated differently than the substance of the nebula, and in some parts of the disk, nebular material may have encountered the arms at supersonic velocities. The disk gas, and solid particles entrained in it, would have been heated to some degree when they passed through shock fronts at the leading edges of the spiral arms. The present paper proposes this was the energetic nebular setting or environment that has long been sought, in which the material now in the planets and chondritic meteorites was thermally processed.

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“…Even in the absence of self-sustained turbulence such as the one generated by the magneto-rotational instability (MRI; Balbus & Hawley 1991;Balbus & Hawley 1998), the solids themselves can generate turbulence due to the backreaction of the drag force onto the gas. Such turbulence can be brought about by Kelvin-Helmholtz instabilities due to the vertical shear present in the sedimented layer of solids (Weidenschilling 1980;Weidenschilling & Cuzzi 1993;Sekiya 1998;Johansen et al 2006), or by streaming instabilities induced by the radial migration of solids particles (Youdin & Goodman 2005;Johansen et al 2006;Paardekooper 2006;. In the turbulent motion, the solids are stirred up by the gas, forming a vertically extended layer where the stellar gravity is balanced by turbulent diffusion (Dubrulle et al 1995;Garaud & Lin 2004).…”

Section: Introductionmentioning

confidence: 99%

Planet formation bursts at the borders of the dead zone in 2D numerical simulations of circumstellar disks

Lyra¹,

Johansen

Zsom

et al. 2009

A&A

167

188

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Context. As accretion in protoplanetary disks is enabled by turbulent viscosity, the border between active and inactive (dead) zones constitutes a location where there is an abrupt change in the accretion flow. The gas accumulation that ensues triggers the Rossby wave instability, which in turn saturates into anticyclonic vortices. It has been suggested that the trapping of solids within them leads to a burst of planet formation on very short timescales. Aims. We study in the formation and evolution of the vortices in greater detail, focusing on the implications for the dynamics of embedded solid particles and planet formation. Methods. We performed two-dimensional global simulations of the dynamics of gas and solids in a non-magnetized thin protoplanetary disk with the Pencil code. We used multiple particle species of radius 1, 10, 30, and 100 cm. We computed the particles' gravitational interaction by a particle-mesh method, translating the particles' number density into surface density and computing the corresponding self-gravitational potential via fast Fourier transforms. The dead zone is modeled as a region of low viscosity. Adiabatic and locally isothermal equations of state are used. Results. The Rossby wave instability is triggered under a variety of conditions, thus making vortex formation a robust process. Inside the vortices, fast accumulation of solids occurs and the particles collapse into objects of planetary mass on timescales as short as five orbits. Because the drag force is size-dependent, aerodynamical sorting ensues within the vortical motion, and the first bound structures formed are composed primarily of similarly-sized particles. In addition to erosion due to ram pressure, we identify gas tides from the massive vortices as a disrupting agent of formed protoplanetary embryos. We find evidence that the backreaction of the drag force from the particles onto the gas modifies the evolution of the Rossby wave instability, with vortices being launched only at later times if this term is excluded from the momentum equation. Even though the gas is not initially gravitationally unstable, the vortices can grow to Q ≈ 1 in locally isothermal runs, which halts the inverse cascade of energy towards smaller wavenumbers. As a result, vortices in models without self-gravity tend to rapidly merge towards a m = 2 or m = 1 mode, while models with self-gravity retain dominant higher order modes (m = 4 or m = 3) for longer times. Non-selfgravitating disks thus show fewer and stronger vortices. We also estimate the collisional velocity history of the particles that compose the most massive embryo by the end of the simulation, finding that the vast majority of them never experienced a collision with another particle at speeds faster than 1 m s −1 . This result lends further support to previous studies showing that vortices provide a favorable environment for planet formation.

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Dust to planetesimals: Settling and coagulation in the solar nebula

Cited by 473 publications

References 23 publications

The evolution of the water distribution in a viscous protoplanetary disk

The evolution of the water distribution in a viscous protoplanetary disk

Processing of chondritic and planetary material in spiral density waves in the nebula

Planet formation bursts at the borders of the dead zone in 2D numerical simulations of circumstellar disks

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