The Role of Drag and Gravity on Dust Concentration in a Gravitationally Unstable Disc

Fuente: arXiv
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Autori principali: Rowther, Sahl, Nealon, Rebecca, Meru, Farzana, Wurster, James, Aly, Hossam, Alexander, Richard, Rice, Ken, Booth, Richard A.
Natura: Preprint
Pubblicazione: 2024
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author Rowther, Sahl
Nealon, Rebecca
Meru, Farzana
Wurster, James
Aly, Hossam
Alexander, Richard
Rice, Ken
Booth, Richard A.
author_facet Rowther, Sahl
Nealon, Rebecca
Meru, Farzana
Wurster, James
Aly, Hossam
Alexander, Richard
Rice, Ken
Booth, Richard A.
contents We carry out three dimensional smoothed particle hydrodynamics simulations to study the role of gravitational and drag forces on the concentration of large dust grains (St > 1) in the spiral arms of gravitationally unstable protoplanetary discs, and the resulting implications for planet formation. We find that both drag and gravity play an important role in the evolution of large dust grains. If we include both, grains that would otherwise be partially decoupled will become well coupled and trace the spirals. For the dust grains most influenced by drag (with Stokes numbers near unity), the dust disc quickly becomes gravitationally unstable and rapidly forms clumps with masses between 0.15 - 6 Earth masses. A large fraction of clumps are below the threshold where runaway gas accretion can occur. However, if dust self-gravity is neglected, the dust is unable to form clumps, despite still becoming trapped in the gas spirals. When large dust grains are unable to feel either gas gravity or drag, the dust is unable to trace the gas spirals. Hence, full physics is needed to properly simulate dust in gravitationally unstable discs. Dust trapping of large grains in spiral arms of discs stable to gas fragmentation could explain planet formation in very young discs by a population of planetesimals formed due to the combined roles of drag and gravity in the earliest stages of a disc's evolution. Furthermore, it highlights that gravitationally unstable discs are not just important for forming gas giants quickly, it can also rapidly form Earth mass bodies.
format Preprint
id arxiv_https___arxiv_org_abs_2401_09380
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Role of Drag and Gravity on Dust Concentration in a Gravitationally Unstable Disc
Rowther, Sahl
Nealon, Rebecca
Meru, Farzana
Wurster, James
Aly, Hossam
Alexander, Richard
Rice, Ken
Booth, Richard A.
Earth and Planetary Astrophysics
We carry out three dimensional smoothed particle hydrodynamics simulations to study the role of gravitational and drag forces on the concentration of large dust grains (St > 1) in the spiral arms of gravitationally unstable protoplanetary discs, and the resulting implications for planet formation. We find that both drag and gravity play an important role in the evolution of large dust grains. If we include both, grains that would otherwise be partially decoupled will become well coupled and trace the spirals. For the dust grains most influenced by drag (with Stokes numbers near unity), the dust disc quickly becomes gravitationally unstable and rapidly forms clumps with masses between 0.15 - 6 Earth masses. A large fraction of clumps are below the threshold where runaway gas accretion can occur. However, if dust self-gravity is neglected, the dust is unable to form clumps, despite still becoming trapped in the gas spirals. When large dust grains are unable to feel either gas gravity or drag, the dust is unable to trace the gas spirals. Hence, full physics is needed to properly simulate dust in gravitationally unstable discs. Dust trapping of large grains in spiral arms of discs stable to gas fragmentation could explain planet formation in very young discs by a population of planetesimals formed due to the combined roles of drag and gravity in the earliest stages of a disc's evolution. Furthermore, it highlights that gravitationally unstable discs are not just important for forming gas giants quickly, it can also rapidly form Earth mass bodies.
title The Role of Drag and Gravity on Dust Concentration in a Gravitationally Unstable Disc
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2401.09380