the coagulation , fragmentation and radial drift of dust in protoplanetary disks
DESCRIPTION
The coagulation , fragmentation and radial drift of dust in protoplanetary disks. F. Brauer, C. Dullemond, Th. Henning. Who am I?. Born march 14th 1980 in Eisenach (Thüringen). Studied physics in Jena 1999-2005. Diploma in Quantum theory (2005). - PowerPoint PPT PresentationTRANSCRIPT
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The coagulationThe coagulation, , fragmentation and radial fragmentation and radial
drift of dustdrift of dust in in protoplanetary disksprotoplanetary disks
F. Brauer, C. Dullemond, Th. Henning
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Who am I?Who am I?
Born march 14th 1980 in Eisenach (Thüringen)
Studied physics in Jena 1999-2005
Diploma in Quantum theory (2005)
Hopefully PhD in 2008
Main hobby .
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What is this talk about?What is this talk about?
Step IStep I - Coagulation at a certain radius - Coagulation at a certain radius
No radial motion, no fragmentationNo radial motion, no fragmentation
Step IIStep II - plus radial motion of the dust - plus radial motion of the dust
Step IIIStep III - plus fragmentation - plus fragmentation
Question:
Can planetesimals form by dust particle coagulation?
(To give an impression about dust particle growth)
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The disk modelThe disk model
DiskDisk
r
- We consider a turbulent disk
- An initial dust to gas ratio of 10-2
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Coagulation at a fixed radiusCoagulation at a fixed radius
NoNo fragmentation fragmentationNoNo radial motion of the dust radial motion of the dust
Step I
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One word about growth mechanisms One word about growth mechanisms
We will consider 3 different growth mechanisms:
1 - Brownian motion
2 - Differential settling
3 - Turbulent coagulation
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The initial distribution
The particle distribution after 1 MyrsThe particle distribution after 1 Myrs( Coagulation / NO radial drift / NO fragmentation )
km size bodies
cm size particles
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Coagulation + radial drift/mixingCoagulation + radial drift/mixing
NoNo fragmentation fragmentation
Step II
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One word about the radial drift of the dust One word about the radial drift of the dust
A maximum radial drift of
some 10 meters per second
- In a protostellar disk the dust particles drift inward
- We adopt the radial drift of individual particles in our model
Which particles drift so fast?
Region of fast radial drift
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Maximum radial drift line
The particle distribution after 1 MyrsThe particle distribution after 1 Myrs( Coagulation + radial drift / No fragmentation )
No km size bodies
No cm size bodies No cm size bodies
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Change some disk parameters?Change some disk parameters?
How do we get larger particles?How do we get larger particles?
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Changing the dust to gas ratio - Changing the dust to gas ratio - Particle distribution after 10Particle distribution after 1033 yrs yrs
( Coagulation + radial drift / NO fragmentation )
Maximum radial drift line
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Coagulation Coagulation + radial drift/mixing+ radial drift/mixing
+ fragmentation+ fragmentation
Step III
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One word about fragmentationOne word about fragmentation• Fragmentation velocity : 10 m/s
• Shattering results
• Complete destruction & Cratering
Small grains collide with larger bodiesBetween equally large bodies
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Dust to gas ratio of 0.05Dust to gas ratio of 0.05
Maximum radial drift
Maximum radial drift
The particle distribution after 10The particle distribution after 1033 yrs yrs( Coagulation + radial drift + fragmentation )
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1 1 - The dust to gas ratio is a highly important disk parameter.
3 things to take away3 things to take away
2 - The dust can growcan grow beyond the radial drift barrier for dust to gas ratios not much higher than 0.01.
3 - The dust can can growgrow beyond the fragmentation barrier for low turbulent disks. (Even though I do not show that here)
ConclusionsConclusions
It is possible to form planetesimals by coagulation.
(Even though it is quite difficult)(Even though it is quite difficult)
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Thank you for your attentionThank you for your attention