Planetesimal Formation by the Gravitational Instability of Dust Ring Structures

We investigate the gravitational instability (GI) of dust ring structures and the formation of planetesimals by their gravitational collapse. The normalized dispersion relation of a self-gravitating ring structure includes two parameters that are related to its width and line mass (the mass per unit...

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Main Authors: Sanemichi Z. Takahashi, Eiichiro Kokubo, Shu-ichiro Inutsuka
Format: Article
Language:English
Published: IOP Publishing 2023-01-01
Series:The Astrophysical Journal
Subjects:
Online Access:https://doi.org/10.3847/1538-4357/ac9fd0
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author Sanemichi Z. Takahashi
Eiichiro Kokubo
Shu-ichiro Inutsuka
author_facet Sanemichi Z. Takahashi
Eiichiro Kokubo
Shu-ichiro Inutsuka
author_sort Sanemichi Z. Takahashi
collection DOAJ
description We investigate the gravitational instability (GI) of dust ring structures and the formation of planetesimals by their gravitational collapse. The normalized dispersion relation of a self-gravitating ring structure includes two parameters that are related to its width and line mass (the mass per unit length). We survey these parameters and calculate the growth rate and wavenumber. Additionally, we investigate the formation of planetesimals by growth of the GI of the ring that is formed by the growth of the secular GI of the protoplanetary disk. We adopt a massive, dust-rich disk as a disk model. We find the range of radii for fragmentation by the ring GI as a function of the width of the ring. The innermost radius for the ring GI is smaller for a smaller ring width. We also determine the range of the initial planetesimal mass resulting from the fragmentation of the ring GI. Our results indicate that the planetesimal mass can be as large as 10 ^28 g at its birth after the fragmentation. It can be as low as about 10 ^25 g if the ring width is 0.1% of the ring radius, and the lower limit increases with the ring width. Furthermore, we obtain approximate formulae for the upper and lower limits of the planetesimal mass. We predict that the planetesimals formed by the ring GI have prograde rotations because of the Coriolis force acting on the contracting dust. This is consistent with the fact that many trans-Neptunian binaries exhibit prograde rotation.
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spelling doaj.art-221af9e10a6e43a78a16f5b0dca5deab2023-09-03T13:08:52ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01945212010.3847/1538-4357/ac9fd0Planetesimal Formation by the Gravitational Instability of Dust Ring StructuresSanemichi Z. Takahashi0https://orcid.org/0000-0003-3038-364XEiichiro Kokubo1https://orcid.org/0000-0002-5486-7828Shu-ichiro Inutsuka2https://orcid.org/0000-0003-4366-6518National Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan ; sanemichi.takahashi@nao.ac.jpNational Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan ; sanemichi.takahashi@nao.ac.jpDepartment of Physics, Nagoya University , Furo-cho, Chikusa-ku, Nagoya, 464-8602 Aichi, JapanWe investigate the gravitational instability (GI) of dust ring structures and the formation of planetesimals by their gravitational collapse. The normalized dispersion relation of a self-gravitating ring structure includes two parameters that are related to its width and line mass (the mass per unit length). We survey these parameters and calculate the growth rate and wavenumber. Additionally, we investigate the formation of planetesimals by growth of the GI of the ring that is formed by the growth of the secular GI of the protoplanetary disk. We adopt a massive, dust-rich disk as a disk model. We find the range of radii for fragmentation by the ring GI as a function of the width of the ring. The innermost radius for the ring GI is smaller for a smaller ring width. We also determine the range of the initial planetesimal mass resulting from the fragmentation of the ring GI. Our results indicate that the planetesimal mass can be as large as 10 ^28 g at its birth after the fragmentation. It can be as low as about 10 ^25 g if the ring width is 0.1% of the ring radius, and the lower limit increases with the ring width. Furthermore, we obtain approximate formulae for the upper and lower limits of the planetesimal mass. We predict that the planetesimals formed by the ring GI have prograde rotations because of the Coriolis force acting on the contracting dust. This is consistent with the fact that many trans-Neptunian binaries exhibit prograde rotation.https://doi.org/10.3847/1538-4357/ac9fd0Gravitational instabilityProtoplanetary disksPlanet formationPlanetesimals
spellingShingle Sanemichi Z. Takahashi
Eiichiro Kokubo
Shu-ichiro Inutsuka
Planetesimal Formation by the Gravitational Instability of Dust Ring Structures
The Astrophysical Journal
Gravitational instability
Protoplanetary disks
Planet formation
Planetesimals
title Planetesimal Formation by the Gravitational Instability of Dust Ring Structures
title_full Planetesimal Formation by the Gravitational Instability of Dust Ring Structures
title_fullStr Planetesimal Formation by the Gravitational Instability of Dust Ring Structures
title_full_unstemmed Planetesimal Formation by the Gravitational Instability of Dust Ring Structures
title_short Planetesimal Formation by the Gravitational Instability of Dust Ring Structures
title_sort planetesimal formation by the gravitational instability of dust ring structures
topic Gravitational instability
Protoplanetary disks
Planet formation
Planetesimals
url https://doi.org/10.3847/1538-4357/ac9fd0
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AT shuichiroinutsuka planetesimalformationbythegravitationalinstabilityofdustringstructures