Planetesimals Dynamics#


Intro paragraph


  • Summary



  • Status: flag alt >

  • Reviewed: ❌

  • Updated: 15/02/2023


  • [Weidenschilling, 1980]: numerical model for computing simultaneous coagulation and settling (gravitational instability/non-Keplerian rotation of nebula), composite process forms km sized planetesimals

Disk instabilities#

  • [Johansen et al., 2014]: hybrid model for planetesimal formation (particle growth starts unaided by self-gravity but later proceeds inside gravitationally collapsing pebble clumps to form planetesimals with a wide range of sizes)



define all those terms

Overcoming The Bouncing Barrier#

2 Scenarios:

  • Gravitational instability

  • Mass transfer

cf [Blum et al., 2014] for good introduction + Modelling and experiments on dust emission from comets etc., homogeneous layers of μm sized dust particles reach tensile strengths (103 – 104 Pa) far higher than water’s sublimation pressure, model of formation by gravitational instability leads to tensile strength of 1 Pa instead => could explain water driven comet activity (minimum size for dust-aggregates: ≈ 1 mm) => cometesimals must have formed by gravitational instability

Gravitational collapse ?#

[Aumatell and Wurm, 2011]: Lab experiments, sublimation of freely levitating ice aggregates, frequent break up, sublimation of drifting ice aggregates might locally increase the density of small dust (silicate)


Let’s jump over the Bouncing Barrier and have a look at thos km bodies that may have formed.


Dynamic Evolution of the Early Solar System#

[Nesvorn´y and Nesvorn´y, 2018]

Overcoming the bouncing barrier#

Electrical charging#

Growth Mechanism#

Sintering ? #

[Okuzumi et al., 2016] (mention ethane in their paper)

  • [Sirono, 2011]: Sintering increases strength of neck in aggregates, sintering region can span whole nebula

  • [Sirono, 2011]: Numerical simulations (sintering of icy dust aggregates), accumulation of fragments in particular region of protoplanetary nebula, planetesimal formation by gravitational instability

Rocky Planet formation#

[Burkhardt et al., 2021] : Two different scenarios for rocky planet formation

From planet formation to planet atmosphere#

[Mollière et al., 2022]