Ejection of dust by elastic waves in collisions between millimeter- and centimeter-sized dust aggregates at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mn>16.5</mml:mn><mml:mspace width="0.3em" /><mml:mtext>to</mml:mtext><mml:mspace width="0.3em" /><mml:mn>37.5</mml:mn><mml:mspace width="0.3em" /><mml:mi mathvariant="normal">m</mml:mi><mml:mo>∕</mml:mo><mml:mi mathvariant="normal">s</mml:mi></mml:mrow></mml:math>impact velocities

Wurm, Gerhard; Paraskov, Georgi; Krauß, Oliver

doi:10.1103/physreve.71.021304

Cited by 34 publications

(28 citation statements)

References 19 publications

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“…which agrees with non-zero-gravity experiments of Wurm et al (2005a), who estimated a mass loss of 10 projectile masses for velocities of more than 1650 cm s −1 . Due to the small variation in projectile mass within each of the two experiments, we apply a power-law in mass and merge both experiments to …”

Section: F2: Erosionsupporting

confidence: 80%

“…) found that the target aggregate is efficiently eroded (F2) if the impact velocities exceed 1500 cm s −1 . This mass loss of the target was also observed in the case of larger projectiles into porous targets (Wurm et al 2005a;Paraskov et al 2007). Similar to the F1 fragmentation, it may occur that one aggregate is porous while the other one is compact.…”

Section: Classification Of the Laboratory Experimentsmentioning

confidence: 61%

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The outcome of protoplanetary dust growth: pebbles, boulders, or planetesimals?

Zsom¹,

Ormel²,

Blum

et al. 2010

A&A

480

632

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Context. The growth processes from protoplanetary dust to planetesimals are not fully understood. Laboratory experiments and theoretical models have shown that collisions among the dust aggregates can lead to sticking, bouncing, and fragmentation. However, no systematic study on the collisional outcome of protoplanetary dust has been performed so far, so that a physical model of the dust evolution in protoplanetary disks is still missing. Aims. We intend to map the parameter space for the collisional interaction of arbitrarily porous dust aggregates. This parameter space encompasses the dust-aggregate masses, their porosities and the collision velocity. With such a complete mapping of the collisional outcomes of protoplanetary dust aggregates, it will be possible to follow the collisional evolution of dust in a protoplanetary disk environment. Methods. We use literature data, perform laboratory experiments, and apply simple physical models to get a complete picture of the collisional interaction of protoplanetary dust aggregates. Results. We found four different kinds of sticking, two kinds of bouncing, and three kinds of fragmentation as possible outcomes in collisions among protoplanetary dust aggregates. Our best collision model distinguishes between porous and compact dust. We also differentiate between collisions among similar-sized and different-sized bodies. All in all, eight combinations of porosity and mass ratio can be discerned. For each of these cases, we present a complete collision model for dust-aggregate masses between 10 −12 and 10 2 g and collision velocities in the range of 10 −4 . . . 10 4 cm s −1 for arbitrary porosities. This model comprises the collisional outcome, the mass(es) of the resulting aggregate(s) and their porosities. Conclusions. We present the first complete collision model for protoplanetary dust. This collision model can be used for the determination of the dust-growth rate in protoplanetary disks.

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Section: F2: Erosionsupporting

confidence: 80%

Section: Classification Of the Laboratory Experimentsmentioning

confidence: 61%

The outcome of protoplanetary dust growth: pebbles, boulders, or planetesimals?

Zsom¹,

Ormel²,

Blum

et al. 2010

A&A

480

632

View full text Add to dashboard Cite

show abstract

“…In experiments with velocities larger than 9 m/s and using compact dust aggregates with a volume filling of ∼33%, sticking is observed together with fragmentation (Wurm et al 2005b;Teiser & Wurm 2009). In similar collision experiments at comparable velocities but with a porous target only fragmentation was observed (Wurm et al 2005a). Due to the fragmentation, sticking and bouncing it is not clear how such a body evolves further.…”

Section: Introductionmentioning

confidence: 84%

“…If further growth is possible depends on the properties of the decimetre-size dust aggregates. Wurm et al (2005a) found that highly porous (granular) dust aggregates are destroyed by impacts of sub-cm bodies at large impact velocities. In contrast, Teiser & Wurm (2009) and Wurm et al (2005b) showed that growth up to ∼60 m/s is possible if the target is compact (33% filling factor).…”

Section: Introductionmentioning

confidence: 99%

Decimetre dust aggregates in protoplanetary discs

Teiser¹,

Wurm²

2009

A&A

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The growth of planetesimals is an essential step in planet formation. Decimetre-size dust agglomerates mark a transition point in this growth process. In laboratory experiments we simulated the formation, evolution, and properties of decimetre-scale dusty bodies in protoplanetary discs. Small sub-mm size dust aggregates consisting of micron-size SiO 2 particles randomly interacted with dust targets of varying initial conditions in a continuous sequence of independent collisions. Impact velocities were 7.7 m/s on average and in the range expected for collisions with decimetre bodies in protoplanetary discs. The targets all evolved by forming dust crusts with up to several cm thickness and a unique filling factor of 31% ± 3%. A part of the projectiles sticks directly. In addition, some projectile fragments slowly return to the target by gravity. All initially porous parts of the surface, i.e. built from the slowly returning fragments, are compacted and firmly attached to the underlying dust layers by the subsequent impacts. Growth is possible at impact angles from 0• (central collision) to 70• . No growth occurs at steeper dust surfaces. We measured the velocity, angle, and size distribution of collision fragments. The average restitution coefficient is 3.8% or 0.29 m/s ejection velocity. Ejecta sizes are comparable to the projectile sizes. The high filling factor is close to the most compact configuration of dust aggregates by local compression (∼33%). This implies that the history of the surface formation and target growth is completely erased. In view of this, the filling factor of 31% seems to be a universal value in the collision experiments of all self-consistently evolving targets at the given impact velocities. We suggest that decimetre and probably larger bodies can simply be characterised by one single filling factor. While gravity dominates re-accretion in the experiments, small fragments will be re-accreted as well in protoplanetary discs by gas drag at the given low ejection velocities. The accretion efficiency in planetesimal growth is model dependent. However, a small fraction of small particles re-accreted by gas flow or direct sticking readily allows growth of dusty bodies in protoplanetary discs in the decimetre range.

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“…The drift can move meter-sized particles all the way in within only 100 orbits (Weidenschilling 1977). Relative velocities of large bodies set another barrier against the accumulation of large particles (Weidenschilling & Cuzzi 1993;Wurm et al 2005a;Ormel & Cuzzi 2007). A recent study by Johansen et al (2006b) shows, however, that planetesimals might be produced by a gravitational collapse in the presence of turbulence.…”

Section: Introductionmentioning

confidence: 99%

Numerical determination of the material properties of porous dust cakes

Paszun

Dominik

2008

A&A

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The formation of planetesimals requires the growth of dust particles through collisions. Micron-sized particles must grow by many orders of magnitude in mass. To understand and model the processes during this growth, both the mechanical properties and the interaction cross sections of aggregates with surrounding gas must be well understood. Recent advances in experimental (laboratory) studies now provide the background for pushing numerical aggregate models to a new level. We present the calibration of a previously tested model of aggregate dynamics. We use plastic deformation of surface asperities as the physical model to match the velocities needed for sticking with experimental results. The modified code is then used to compute both the compression strength and the velocity of sound in the aggregate at different densities. We compare these predictions with experimental results and conclude that the new code is capable of studying the properties of small aggregates.

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Ejection of dust by elastic waves in collisions between millimeter- and centimeter-sized dust aggregates at16.5to37.5m∕simpact velocities

Cited by 34 publications

References 19 publications

The outcome of protoplanetary dust growth: pebbles, boulders, or planetesimals?

The outcome of protoplanetary dust growth: pebbles, boulders, or planetesimals?

Decimetre dust aggregates in protoplanetary discs

Numerical determination of the material properties of porous dust cakes

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