Thousands of planetesimals : Simulating the streaming instability in very large computational domains
(2024) In Astronomy and Astrophysics 691.- Abstract
The streaming instability is a mechanism whereby pebble-sized particles in protoplanetary discs spontaneously come together in dense filaments, which collapse gravitationally to form planetesimals upon reaching the Roche density. The extent of the filaments along the orbital direction is nevertheless poorly characterised, due to a focus in the literature on small simulation domains where the behaviour of the streaming instability on large scales cannot be determined. We present here computer simulations of the streaming instability in boxes with side lengths up to 6.4 scale heights in the plane. This is 32 times larger than typically considered simulation domains and nearly a factor 1000 times the volume. We show that the azimuthal... (More)
The streaming instability is a mechanism whereby pebble-sized particles in protoplanetary discs spontaneously come together in dense filaments, which collapse gravitationally to form planetesimals upon reaching the Roche density. The extent of the filaments along the orbital direction is nevertheless poorly characterised, due to a focus in the literature on small simulation domains where the behaviour of the streaming instability on large scales cannot be determined. We present here computer simulations of the streaming instability in boxes with side lengths up to 6.4 scale heights in the plane. This is 32 times larger than typically considered simulation domains and nearly a factor 1000 times the volume. We show that the azimuthal extent of filaments in the non-linear state of the streaming instability is limited to approximately one gas scale height. The streaming instability will therefore not transform the pebble density field into axisymmetric rings; rather the non-linear state of the streaming instability appears as a complex structure of loosely connected filaments. Including the self-gravity of the pebbles, our simulations form up to 4000 planetesimals. This allows us to probe the high-mass end of the initial mass function of planetesimals with much higher statistical confidence than previously. We find that this end is well-described by a steep exponential tapering. Since the resolution of our simulations is moderate - a necessary trade-off given the large domains - the mass distribution is incomplete at the low-mass end. When putting comparatively less weight on the numbers at low masses, at intermediate masses we nevertheless reproduce the power-law shape of the distribution established in previous studies.
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- author
- Schäfer, Urs LU ; Johansen, Anders LU ; Haugbølle, Troels and Nordlund, A. Ke
- organization
- publishing date
- 2024-11-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Hydrodynamics, Instabilities, Methods: numerical, Planets and satellites: formation, Protoplanetary disks
- in
- Astronomy and Astrophysics
- volume
- 691
- article number
- A258
- publisher
- EDP Sciences
- external identifiers
-
- scopus:85209889652
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361/202450639
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © The Authors 2024.
- id
- 5186c1cd-5bd7-4a18-b324-63e8fd9d285e
- date added to LUP
- 2025-01-13 16:49:26
- date last changed
- 2025-04-04 14:14:48
@article{5186c1cd-5bd7-4a18-b324-63e8fd9d285e,
abstract = {{<p>The streaming instability is a mechanism whereby pebble-sized particles in protoplanetary discs spontaneously come together in dense filaments, which collapse gravitationally to form planetesimals upon reaching the Roche density. The extent of the filaments along the orbital direction is nevertheless poorly characterised, due to a focus in the literature on small simulation domains where the behaviour of the streaming instability on large scales cannot be determined. We present here computer simulations of the streaming instability in boxes with side lengths up to 6.4 scale heights in the plane. This is 32 times larger than typically considered simulation domains and nearly a factor 1000 times the volume. We show that the azimuthal extent of filaments in the non-linear state of the streaming instability is limited to approximately one gas scale height. The streaming instability will therefore not transform the pebble density field into axisymmetric rings; rather the non-linear state of the streaming instability appears as a complex structure of loosely connected filaments. Including the self-gravity of the pebbles, our simulations form up to 4000 planetesimals. This allows us to probe the high-mass end of the initial mass function of planetesimals with much higher statistical confidence than previously. We find that this end is well-described by a steep exponential tapering. Since the resolution of our simulations is moderate - a necessary trade-off given the large domains - the mass distribution is incomplete at the low-mass end. When putting comparatively less weight on the numbers at low masses, at intermediate masses we nevertheless reproduce the power-law shape of the distribution established in previous studies.</p>}},
author = {{Schäfer, Urs and Johansen, Anders and Haugbølle, Troels and Nordlund, A. Ke}},
issn = {{0004-6361}},
keywords = {{Hydrodynamics; Instabilities; Methods: numerical; Planets and satellites: formation; Protoplanetary disks}},
language = {{eng}},
month = {{11}},
publisher = {{EDP Sciences}},
series = {{Astronomy and Astrophysics}},
title = {{Thousands of planetesimals : Simulating the streaming instability in very large computational domains}},
url = {{http://dx.doi.org/10.1051/0004-6361/202450639}},
doi = {{10.1051/0004-6361/202450639}},
volume = {{691}},
year = {{2024}},
}