Formation of Inner Planets in the Presence of a Cold Jupiter: Orbital Evolution and Relative Velocities of Planetesimals

We investigate the orbital evolution of planetesimals in the inner disk in the presence of nebula gas and a (proto-) cold Jupiter. By varying the mass, eccentricity, and semimajor axis of the planet, we study the dependence of the relative velocities of the planetesimals on these parameters. For cla...

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Main Authors: Kangrou Guo, Eiichiro Kokubo
Format: Article
Language:English
Published: IOP Publishing 2023-01-01
Series:The Astrophysical Journal
Subjects:
Online Access:https://doi.org/10.3847/1538-4357/acf31d
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author Kangrou Guo
Eiichiro Kokubo
author_facet Kangrou Guo
Eiichiro Kokubo
author_sort Kangrou Guo
collection DOAJ
description We investigate the orbital evolution of planetesimals in the inner disk in the presence of nebula gas and a (proto-) cold Jupiter. By varying the mass, eccentricity, and semimajor axis of the planet, we study the dependence of the relative velocities of the planetesimals on these parameters. For classic small planetesimals (10 ^16 –10 ^20 g) whose mutual gravitational interaction is negligible, gas drag introduces a size-dependent alignment of orbits and keeps the relative velocity low for similar-sized bodies, while preventing orbital alignment for different-sized planetesimals. Regardless of the location and the mass ratio of the planetesimals, increasing the mass and eccentricity or decreasing the orbital distance of the planet always lead to higher relative velocities of the planetesimals. However, for massive planetesimals, the interplay of viscous stirring, gas damping, and secular perturbation results in the lower velocity dispersion of equal-sized planetesimals when the planet is more massive or when it is located on a closer or more eccentric orbit. The random velocities of such planetesimals remain almost unperturbed when the planet is located beyond Jupiter’s current orbit or when it is less massive or less eccentric than Jupiter. Unlike small planetesimals, such large planetesimals can grow in a runaway fashion, as in the unperturbed case. Our results imply that the presence of a cold Jupiter does not impede the formation of inner rocky planets through planetesimal accretion, provided that the planetesimals are initially large.
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spelling doaj.art-d55eba57929a4c728b9e9c258ee58ff62023-10-09T14:59:46ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01955210910.3847/1538-4357/acf31dFormation of Inner Planets in the Presence of a Cold Jupiter: Orbital Evolution and Relative Velocities of PlanetesimalsKangrou Guo0https://orcid.org/0000-0001-6870-3114Eiichiro Kokubo1https://orcid.org/0000-0002-5486-7828Tsung-Dao Lee Institute, Shanghai Jiao Tong University , 520 Shengrong Road, Shanghai 201210, People’s Republic of China ; carol.guo@sjtu.edu.cn; The University of Tokyo , 113-8654, 7 Chome-3-1, Hongo Bunkyo City, Tokyo, Japan; National Astronomical Observatory of Japan , 181-8588, 2 Chome-21-1, Osawa Mitaka City, Tokyo, JapanThe University of Tokyo , 113-8654, 7 Chome-3-1, Hongo Bunkyo City, Tokyo, Japan; National Astronomical Observatory of Japan , 181-8588, 2 Chome-21-1, Osawa Mitaka City, Tokyo, JapanWe investigate the orbital evolution of planetesimals in the inner disk in the presence of nebula gas and a (proto-) cold Jupiter. By varying the mass, eccentricity, and semimajor axis of the planet, we study the dependence of the relative velocities of the planetesimals on these parameters. For classic small planetesimals (10 ^16 –10 ^20 g) whose mutual gravitational interaction is negligible, gas drag introduces a size-dependent alignment of orbits and keeps the relative velocity low for similar-sized bodies, while preventing orbital alignment for different-sized planetesimals. Regardless of the location and the mass ratio of the planetesimals, increasing the mass and eccentricity or decreasing the orbital distance of the planet always lead to higher relative velocities of the planetesimals. However, for massive planetesimals, the interplay of viscous stirring, gas damping, and secular perturbation results in the lower velocity dispersion of equal-sized planetesimals when the planet is more massive or when it is located on a closer or more eccentric orbit. The random velocities of such planetesimals remain almost unperturbed when the planet is located beyond Jupiter’s current orbit or when it is less massive or less eccentric than Jupiter. Unlike small planetesimals, such large planetesimals can grow in a runaway fashion, as in the unperturbed case. Our results imply that the presence of a cold Jupiter does not impede the formation of inner rocky planets through planetesimal accretion, provided that the planetesimals are initially large.https://doi.org/10.3847/1538-4357/acf31dPlanetesimalsPlanet formationOrbital evolutionPlanetary dynamics
spellingShingle Kangrou Guo
Eiichiro Kokubo
Formation of Inner Planets in the Presence of a Cold Jupiter: Orbital Evolution and Relative Velocities of Planetesimals
The Astrophysical Journal
Planetesimals
Planet formation
Orbital evolution
Planetary dynamics
title Formation of Inner Planets in the Presence of a Cold Jupiter: Orbital Evolution and Relative Velocities of Planetesimals
title_full Formation of Inner Planets in the Presence of a Cold Jupiter: Orbital Evolution and Relative Velocities of Planetesimals
title_fullStr Formation of Inner Planets in the Presence of a Cold Jupiter: Orbital Evolution and Relative Velocities of Planetesimals
title_full_unstemmed Formation of Inner Planets in the Presence of a Cold Jupiter: Orbital Evolution and Relative Velocities of Planetesimals
title_short Formation of Inner Planets in the Presence of a Cold Jupiter: Orbital Evolution and Relative Velocities of Planetesimals
title_sort formation of inner planets in the presence of a cold jupiter orbital evolution and relative velocities of planetesimals
topic Planetesimals
Planet formation
Orbital evolution
Planetary dynamics
url https://doi.org/10.3847/1538-4357/acf31d
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