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Initial mass function of planetesimals formed by the streaming instability

Schäfer, Urs; Yang, Chao Chin LU and Johansen, Anders LU (2017) In Astronomy and Astrophysics 597.
Abstract

The streaming instability is a mechanism to concentrate solid particles into overdense filaments that undergo gravitational collapse and form planetesimals. However, it remains unclear how the initial mass function of these planetesimals depends on the box dimensions of numerical simulations. To resolve this, we perform simulations of planetesimal formation with the largest box dimensions to date, allowing planetesimals to form simultaneously in multiple filaments that can only emerge within such large simulation boxes. In our simulations, planetesimals with sizes between 80 km and several hundred kilometers form. We find that a power law with a rather shallow exponential cutoff at the high-mass end represents the cumulative birth mass... (More)

The streaming instability is a mechanism to concentrate solid particles into overdense filaments that undergo gravitational collapse and form planetesimals. However, it remains unclear how the initial mass function of these planetesimals depends on the box dimensions of numerical simulations. To resolve this, we perform simulations of planetesimal formation with the largest box dimensions to date, allowing planetesimals to form simultaneously in multiple filaments that can only emerge within such large simulation boxes. In our simulations, planetesimals with sizes between 80 km and several hundred kilometers form. We find that a power law with a rather shallow exponential cutoff at the high-mass end represents the cumulative birth mass function better than an integrated power law. The steepness of the exponential cutoff is largely independent of box dimensions and resolution, while the exponent of the power law is not constrained at the resolutions we employ. Moreover, we find that the characteristic mass scale of the exponential cutoff correlates with the mass budget in each filament. Together with previous studies of high-resolution simulations with small box domains, our results therefore imply that the cumulative birth mass function of planetesimals is consistent with an exponentially tapered power law with a power-law exponent of approximately -1.6 and a steepness of the exponential cutoff in the range of 0.3-0.4.

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organization
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Contribution to journal
publication status
published
subject
keywords
Hydrodynamics, Instabilities, Methods: Numerical, Planets and satellites: Formation, Protoplanetary disks
in
Astronomy and Astrophysics
volume
597
publisher
EDP Sciences
external identifiers
  • scopus:85008689705
  • wos:000392392900127
ISSN
0004-6361
DOI
10.1051/0004-6361/201629561
language
English
LU publication?
yes
id
60412928-8fd3-4af4-83c9-bf2af29cf9ff
date added to LUP
2017-03-16 13:26:03
date last changed
2018-04-15 04:42:09
@article{60412928-8fd3-4af4-83c9-bf2af29cf9ff,
  abstract     = {<p>The streaming instability is a mechanism to concentrate solid particles into overdense filaments that undergo gravitational collapse and form planetesimals. However, it remains unclear how the initial mass function of these planetesimals depends on the box dimensions of numerical simulations. To resolve this, we perform simulations of planetesimal formation with the largest box dimensions to date, allowing planetesimals to form simultaneously in multiple filaments that can only emerge within such large simulation boxes. In our simulations, planetesimals with sizes between 80 km and several hundred kilometers form. We find that a power law with a rather shallow exponential cutoff at the high-mass end represents the cumulative birth mass function better than an integrated power law. The steepness of the exponential cutoff is largely independent of box dimensions and resolution, while the exponent of the power law is not constrained at the resolutions we employ. Moreover, we find that the characteristic mass scale of the exponential cutoff correlates with the mass budget in each filament. Together with previous studies of high-resolution simulations with small box domains, our results therefore imply that the cumulative birth mass function of planetesimals is consistent with an exponentially tapered power law with a power-law exponent of approximately -1.6 and a steepness of the exponential cutoff in the range of 0.3-0.4.</p>},
  articleno    = {A69},
  author       = {Schäfer, Urs and Yang, Chao Chin and Johansen, Anders},
  issn         = {0004-6361},
  keyword      = {Hydrodynamics,Instabilities,Methods: Numerical,Planets and satellites: Formation,Protoplanetary disks},
  language     = {eng},
  month        = {01},
  publisher    = {EDP Sciences},
  series       = {Astronomy and Astrophysics},
  title        = {Initial mass function of planetesimals formed by the streaming instability},
  url          = {http://dx.doi.org/10.1051/0004-6361/201629561},
  volume       = {597},
  year         = {2017},
}