Breaking through: The effects of a velocity distribution on barriers to dust growth

By F. Windmark, T. Birnstiel, C. Ormel, C. Dullemond. 2012

151 citations recorded by the source corpus.

It is unknown how far dust growth can proceed by coagulation. Obstacles to collisional growth are the fragmentation and bouncing barriers. However, in all previous simulations of the dust-size evolution in protoplanetary disks, only the mean collision velocity has been considered, neglecting that a small but possibly important fraction of the collisions will occur at both much lower and higher velocities. We study the effect of the probability distribution of impact velocities on the collisional dust growth barriers. Assuming a Maxwellian velocity distribution for colliding particles to determine the fraction of sticking, bouncing, and fragmentation, we implement this in a dust-size evolution code. We also calculate the probability of growing through the barriers and the growth timescale in these regimes. We find that the collisional growth barriers are not as sharp as previously thought. With the existence of low-velocity collisions, a small fraction of the particles manage to grow to masses orders of magnitude above the main population. A particle velocity distribution softens the fragmentation barrier and removes the bouncing barrier. It broadens the size distribution in a natural way, allowing the largest particles to become the first seeds that initiate sweep-up growth towards planetesimal sizes.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/a4160a4840e86f3bac1aec6f516b0355fd98d6f2

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In Astronomy and Astrophysics

1. Anders Johansen
2. T. Birnstiel
3. M. Fang
4. E. Chiang
5. Eve J. Lee
6. Cecilia Ceccarelli
7. P. Caselli
8. Michiel Lambrechts

In Instrumentation

1. Anders Johansen
2. M. Fang
3. Eve J. Lee
4. Cecilia Ceccarelli
5. G. Kovacs
6. E. Chiang
7. T. Birnstiel
8. P. Caselli

Citations in the corpus

• Our astrochemical heritage (2012, background): “…(e.g., Güttler et al. 2010; Schräpler et al. 2012), numerical simulations (e.g., Zsom et al. 2011) and theoretical work (e.g., Dominik et al. 2007; Windmark et al. 2012) are fundamental to progress in this field and an effort has to be made to link dust coagulation models with astrochemistry.”
• Dust Evolution and the Formation of Planetesimals (2016, methodology): “Particles will continue to grow beyond the bouncing barrier, as found by Windmark et al. (2012b).”
• BREEDING SUPER-EARTHS AND BIRTHING SUPER-PUFFS IN TRANSITIONAL DISKS (2015, background): “Grain growth in disks can be fast, especially at the high densities that prevail inside 1 AU (e.g., Blum & Wurm 2000; Windmark et al. 2012).”
• The primordial nucleus of comet 67P/Churyumov-Gerasimenko (2015, background): “According to Windmark et al. (2012a) these large aggregates can grow from smaller ones if the collisions are violent enough to fragment the small ones but gentle enough not to erode the large ones.”