Accelerated planetesimal growth in self-gravitating protoplanetary discs

By W. Rice, G. Lodato, J. E. Pringle, Philip Armitage, Ian A. Bonnell. 2004

169 citations recorded by the source corpus.

In this paper we consider the evolution of small planetesimals (radii ∼1‐10 m) in marginally stable, self-gravitating protoplanetary discs. The drag force between the disc gas and the embedded planetesimals generally causes the planetesimals to drift inwards through the disc at a rate that depends on the particle size. In a marginally stable, self-gravitating disc, however, the planetesimals are significantly influenced by the non-axisymmetric spiral structures resulting from the growth of the gravitational instability. The drag force now causes the planetesimals to drift towards the peaks of the spiral arms where the density and pressure are highest. For small particles that are strongly coupled to the disc gas, and for large particles that have essentially decoupled from the disc gas, the effect is not particularly significant. Intermediate-sized particles, which would generally have the largest radial drift rates, do, however, become significantly concentrated at the peaks of the spiral arms. These high-density regions may persist for, of order, an orbital period and may attain densities comparable to that of the disc gas. Although at the end of the simulation only ∼25 per cent of the planetesimal particles lie in regions of enhanced density, during the course of the simulation at least 75 per cent of the planetesimal particles have at some stage been in a such a region. We find that the concentration of particles in the spiral arms results in an increased collision rate, an effect that could significantly accelerate planetesimal growth. The density enhancements may also be sufficient for the growth of planetesimals through direct gravitational collapse. The interaction between small planetesimals and self-gravitating spiral structures may therefore play an important role in the formation of large planetesimals that will ultimately coagulate to form terrestrial planets or the cores of gas/ice giant planets.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/ee09d3c5b8210ce72a90bce54d93dd44cb254012

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Citations in the corpus

Multiple Disk Gaps and Rings Generated by a Single Super-Earth (2017, background): “By contrast, density waves excited by gravitational instability do rotate at approximately the local Keplerian velocity and are able to concentrate particles of certain sizes (Rice et al. 2004).”
Gravitational Instabilities in Circumstellar Disks (2016, methodology): “Rice et al. (2004) using 3D, global SPH simulations of gas and dust coupled via drag with a simple algorithm first demonstrated numerically that these traps work effectively in selfgravitating disks.”
Planet formation bursts at the borders of the dead zone in 2D numerical simulations of circumstellar disks (2009, background): “Such problem is particularly severe in the high mass disks investigated by Rice et al. (2004) and Rice et al. (2006), where the typical speeds of the boulders upon encounters are comparable to the sound speed.”
THE FORMATION MECHANISM OF GAS GIANTS ON WIDE ORBITS (2009, unknown): “The maximum-mass disks hold between 1/4 and 1/3 of the system mass and may undergo global gravitational instabilities that aid planet/planetesimal formation (e.g. Adams et al. 1989; Rice et al. 2004; Lodato & Rice 2005), which we examine in §5.”
Planet formation and migration (2005, methodology): “Numerical simulations of 1–10 m sized objects in marginally stable, self–gravitating disks by Rice et al (2004) show that the drag force causes the solid objects to drift towards the peaks of the spiral arms where the density and pressure are highest, in accord with the behavior predicted by using…”
Dust filtration at gap edges: Implications for the spectral energy distributions of discs with embedded planets (2006, background): “(5) In equation (5), Re is the Reynolds number which can be shown to be given by (see for example Rice et al. (2004)) Re = 4 ( a λ ) ( u cs ) .”
Standing on the shoulders of giants : Trojan Earths and vortex trapping in low mass self-gravitating protoplanetary disks of gas and solids (2008, methodology): “Studies with self gravity to follow the collapse are restricted to local boxes (Johansen et al. 2007) and the massive disk case (Rice et al. 2004, Rice et al. 2006).”
Toward Planetesimals: Dense Chondrule Clumps in the Protoplanetary Nebula (2008, background): “…found that transient “pressure ridges” arise in the gas in association with spiral density waves or vortical structures (Haghighipour and Boss 2003, Rice et al 2004, Johansen et al 2007); in such regions, the local radial pressure gradient and headwind diminish (other regions will have unusually…”
Gravoturbulent Formation of Planetesimals (2005, background): “This is very similar to the concentrations that Rice et al. (2004) find in the spiral arms of self-gravitating discs.”
Asteroids Were Born Big (2009, background): “How can the meter-sized barrier be overcome? Two intriguing possibilities come from a recent conceptual breakthrough; new models (Johansen et al., 2007; Cuzzi et al., 2008) show that large planetesimals can form directly from the concentration of small solid particles in the turbulent structures of ”