J/A+A/559/A62 Simulations of dust aggregates through collisions (Wada+, 2013)
Growth efficiency of dust aggregates through collisions with large mass-ratios.
Wada K., Tanaka H., Okuzumi S., Kobayashi H., Suyama T., Kimura H.,
Yamamoto T.
<Astron. Astrophys. 559, A62 (2013)>
=2013A&A...559A..62W 2013A&A...559A..62W
ADC_Keywords: Models ; Planets
Keywords: planets and satellites: formation - protoplanetary disks -
methods: numerical
Abstract:
Collisional growth of dust aggregates is an essential process to form
planetesimals in protoplanetary disks, but disruption through
high-velocity collisions (disruption barrier) could prohibit the dust
growth. Mass transfer through highly different-sized collisions has
been suggested to be a way to circumvent the disruption barrier.
We examine how the collisional growth efficiency of dust aggregates at
different impact parameters depends on the size and the mass-ratio of
colliding aggregates.
We use an N-body code to numerically simulate the collisions of
different-sized aggregates.
Our results show that large values of the impact parameter are
important and the growth efficiency averaged over the impact parameter
does not depend on the aggregate size although the growth efficiency
for nearly head-on collisions increases with size. We also find that
the averaged growth efficiency tends to increase with increasing the
mass-ratio of colliding aggregates. However, the critical collision
velocity, above which the growth efficiency becomes negative, does not
strongly depend on the mass-ratio. These results indicate icy dust can
grow through high-velocity offset collisions at several tens of m/s,
the maximum collision velocity experienced in protoplanetary disks,
whereas it is still difficult for silicate dust to grow in
protoplanetary disks.
Description:
We performed 972 simulation runs of collisions of different-sized BPCA
aggregates. For each run, we present the number of particles of
projectile N_proj, and target aggregates N_target, random number to
make aggregates, collision velocity u_col, square of impact parameter
(b/bmax)2, growth efficiency f=(Nlarge-Ntarget)/Nproj, and
total ejecta mass ratio Mej/Mproj.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 45 972 Numerical data for each run
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Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Np Number Nproj of particles of projectile
aggregate (500, 2000 or 8000)
6- 11 I6 --- Nt Number of particles of target aggregate
(32000, 128000 or 512000)
13 I1 --- RN [1/3] Random number to make aggregates
15- 22 F8.4 m/s ucol [15/350] Collision velocity
24- 28 F5.3 --- b2 [0/1] Square of impact parameter (b/bmax)2
30- 37 F8.4 --- f [-12/1] Growth efficiency
39- 45 F7.4 --- Mej/Mp Total ejecta mass ratio Mej/Mproj
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Acknowledgements:
Koji Wada, wada(at)perc.it-chiba.ac.jp
(End) Koji Wada [PERC/Chitech, Japan], Patricia Vannier [CDS] 16-Sep-2013