Post on 23-Feb-2016
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Dullemond & Dominik 2005
Brownian motion growth: self-similar
One-particle model
Equator
Sedimentation-driven growth („rainshower“)
One-particle model
Equator
Sedimentation-driven growth („rainshower“)
One-particle model
Equator
Sedimentation-driven growth („rainshower“)
One-particle model
Equator
Sedimentation-driven growth („rainshower“)
Warning: Not to scale! ;-)
Sedimentation-driven growth („rainshower“)Equation of settling of the big dust grain:
Equation of growth by sweep-up as the big grain falls:
Relation between m(t) and a(t):
Distribution of the small dust:
Sedimentation-driven growth („rainshower“)
Dullemond & Dominik (2005)
“Rainshower” in a disk
Dullemond & Dominik (2005)
Rain falling from a cumulus congestus cloud
Parallel with meteorology
Now with convection
Dullemond & Dominik (2005)
Cumulonimbus cloud, most probably with severe hail
Parallel with meteorology
Layered structure of giant hail stone
Parallel with meteorology
Main problem: high velocities
Particle size [meter]
30 m/s =100 km/h !!
Dust coagulation+fragmentation model
Birnstiel, Dullemond & Ormel 2010
Grain size [cm]10-4 10-2 100
10-8
10-6
10-4
10-2Σ d
ust [
g/cm
2 ]
Dust coagulation+fragmentation model
10-8
10-6
10-4
10-2Σ d
ust [
g/cm
2 ]
Grain size [cm]10-4 10-2 100
Birnstiel, Dullemond & Ormel 2010
Meter-size barrier
1m 1mm 1m 1km
Growth from ‘dust’ to planetary building blocks
Brownianmotion
Differentialsettling Turbulence
Aggregation
Meter-size barrier
Sweep-up growthFragmentation
Rapid radial drift
More barriers...
1m 1mm 1m 1km
Growth from ‘dust’ to planetary building blocks
Brownianmotion
Differentialsettling Turbulence
Meter-size barrier
Sweep-up growthFragmentation
Rapid radial drift
Aggregation
Bouncing barrier
Zsom et al. 2010, Güttler et al. 2010
Charge barrier
Okuzumi 2009
The “Lucky One” idea
1m 1mm 1m 1km
Growth from ‘dust’ to planetary building blocks
Brownianmotion
Differentialsettling Turbulence
Meter-size barrier
Sweep-up growthFragmentation
Rapid radial drift
Aggregation
Let’s focus on the fragmentation barrier
Windmark et al. 2012
How to create these seeds? Perhaps velocity distributions:Garaud et al. 2013; Windmark et al. 2012
Low sticking efficiency
Par
ticle
abu
ndan
ceThe “Lucky One” idea
All the different collision outcomes...
Güttler et al. 2010
Fluffy grains, compaction, bouncing...
Zsom et al. 2010