Dust Growth in ALMA Rings: II. Dusty Rossby Wave Instability

Fuente: arXiv
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Main Authors: Cui, Can, Gerbig, Konstantin, Li, Ya-Ping, Xu, Ziyan, Li, Rixin, Yu, Cong, Lin, Min-Kai, Yuan, Feng
Format: Preprint
Published: 2025
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_version_ 1866915266394324992
author Cui, Can
Gerbig, Konstantin
Li, Ya-Ping
Xu, Ziyan
Li, Rixin
Yu, Cong
Lin, Min-Kai
Yuan, Feng
author_facet Cui, Can
Gerbig, Konstantin
Li, Ya-Ping
Xu, Ziyan
Li, Rixin
Yu, Cong
Lin, Min-Kai
Yuan, Feng
contents Annular substructures serve as ideal venues for planetesimal formation. In this series, we investigate the linear stage of dust growth within rings. The first paper examines the global streaming instability, while this study focuses on the dusty Rossby wave instability (DRWI). We perform a linear analysis of the two-fluid equations on a background pressure bump, representing annular substructures. The spectral code \textsc{Dedalus} is used to solve the linear eigenvalue problem. We identify two distinct DRWI modes: Type I, which originates from dust-modified gas RWI, and Type II, which results from dust-gas coupling. These modes never coexist for a given azimuthal wavenumber $\ky$, but transition between each other as $\ky$ varies. Type I modes are driven by the advection of background vorticity, whereas Type II modes involve two primary waves: Rossby waves, driven by advection, and thin waves, driven by dust-gas drag. Finally, we assess the relevance of DRWI in ALMA rings using DSHARP sources. Our findings suggest that Type I modes could explain the absence of azimuthal asymmetries in many ALMA disks, whereas Type II modes are entirely absent in all eight observed rings, implying that unresolved narrow rings or alternative mechanisms may play a role in dust growth within annular substructures.
format Preprint
id arxiv_https___arxiv_org_abs_2504_05095
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dust Growth in ALMA Rings: II. Dusty Rossby Wave Instability
Cui, Can
Gerbig, Konstantin
Li, Ya-Ping
Xu, Ziyan
Li, Rixin
Yu, Cong
Lin, Min-Kai
Yuan, Feng
Earth and Planetary Astrophysics
Annular substructures serve as ideal venues for planetesimal formation. In this series, we investigate the linear stage of dust growth within rings. The first paper examines the global streaming instability, while this study focuses on the dusty Rossby wave instability (DRWI). We perform a linear analysis of the two-fluid equations on a background pressure bump, representing annular substructures. The spectral code \textsc{Dedalus} is used to solve the linear eigenvalue problem. We identify two distinct DRWI modes: Type I, which originates from dust-modified gas RWI, and Type II, which results from dust-gas coupling. These modes never coexist for a given azimuthal wavenumber $\ky$, but transition between each other as $\ky$ varies. Type I modes are driven by the advection of background vorticity, whereas Type II modes involve two primary waves: Rossby waves, driven by advection, and thin waves, driven by dust-gas drag. Finally, we assess the relevance of DRWI in ALMA rings using DSHARP sources. Our findings suggest that Type I modes could explain the absence of azimuthal asymmetries in many ALMA disks, whereas Type II modes are entirely absent in all eight observed rings, implying that unresolved narrow rings or alternative mechanisms may play a role in dust growth within annular substructures.
title Dust Growth in ALMA Rings: II. Dusty Rossby Wave Instability
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2504.05095