Planet Migration in Windy Discs

Fuente: arXiv
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Autores principales: Wu, Yinhao, Chen, Yi-Xian
Formato: Preprint
Publicado: 2024
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author Wu, Yinhao
Chen, Yi-Xian
author_facet Wu, Yinhao
Chen, Yi-Xian
contents Accretion of protoplanetary discs (PPDs) could be driven by MHD disc winds rather than turbulent viscosity. With a dynamical prescription for angular momentum transport induced by disc winds, we perform 2D simulations of PPDs to systematically investigate the rate and direction of planet migration in a windy disc. We find that the the strength of disc winds influences the corotation region similarly to the "desaturation" effect of viscosity. The magnitude and direction of torque depend sensitively on the hierarchy between the radial advection timescale across the horseshoe due to disc wind $τ_{\rm dw}$, the horsehoe libration timescale $τ_{\rm lib}$ and U-turn timescale $τ_{\rm U-turn}$. Initially, as wind strength increases and the advection timescale shortens, a non-linear horseshoe drag emerges when $τ_{\rm dw} \lesssim τ_{\rm lib}$, which tends to drive strong outward migration. Subsequently, the drag becomes linear and planets typically still migrate inward when $τ_{\rm dw} \lesssim τ_{\rm U-turn} \sim τ_{\rm lib}h$, where $h$ is the disc aspect ratio. For a planet with mass ratio of $\sim 10^{-5}$, the zone of outward migration sandwiched between inner and outer inward migration zones corresponds to $\sim $ 10-100 au in a PPD with accretion rates between $10^{-8}$ and $10^{-7}$ $M_\odot \text{yr}^{-1}$.
format Preprint
id arxiv_https___arxiv_org_abs_2410_19731
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Planet Migration in Windy Discs
Wu, Yinhao
Chen, Yi-Xian
Earth and Planetary Astrophysics
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
Accretion of protoplanetary discs (PPDs) could be driven by MHD disc winds rather than turbulent viscosity. With a dynamical prescription for angular momentum transport induced by disc winds, we perform 2D simulations of PPDs to systematically investigate the rate and direction of planet migration in a windy disc. We find that the the strength of disc winds influences the corotation region similarly to the "desaturation" effect of viscosity. The magnitude and direction of torque depend sensitively on the hierarchy between the radial advection timescale across the horseshoe due to disc wind $τ_{\rm dw}$, the horsehoe libration timescale $τ_{\rm lib}$ and U-turn timescale $τ_{\rm U-turn}$. Initially, as wind strength increases and the advection timescale shortens, a non-linear horseshoe drag emerges when $τ_{\rm dw} \lesssim τ_{\rm lib}$, which tends to drive strong outward migration. Subsequently, the drag becomes linear and planets typically still migrate inward when $τ_{\rm dw} \lesssim τ_{\rm U-turn} \sim τ_{\rm lib}h$, where $h$ is the disc aspect ratio. For a planet with mass ratio of $\sim 10^{-5}$, the zone of outward migration sandwiched between inner and outer inward migration zones corresponds to $\sim $ 10-100 au in a PPD with accretion rates between $10^{-8}$ and $10^{-7}$ $M_\odot \text{yr}^{-1}$.
title Planet Migration in Windy Discs
topic Earth and Planetary Astrophysics
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2410.19731