Document Type

Article

Publication Date

2-16-2021

Publication Title

Monthly Notices of the Royal Astronomical Society

Volume

502

Issue

4

First page number:

5325

Last page number:

5339

Abstract

Recent ALMA molecular line observations have revealed 3D gas velocity structure in protoplanetary discs, shedding light on mechanisms of disc accretion and structure formation. (1) By carrying out viscous simulations, we confirm that the disc's velocity structure differs dramatically using vertical stress profiles from different accretion mechanisms. Thus, kinematic observations tracing flows at different disc heights can potentially distinguish different accretion mechanisms. On the other hand, the disc surface density evolution is mostly determined by the vertically integrated stress. The sharp disc outer edge constrained by recent kinematic observations can be caused by a radially varying alpha in the disc. (2) We also study kinematic signatures of a young planet by carrying out 3D planet-disc simulations. The relationship between the planet mass and the 'kink' velocity is derived, showing a linear relationship with little dependence on disc viscosity, but some dependence on disc height when the planet is massive (e.g. 10M(J)). We predict the 'kink' velocities for the potential planets in DSHARP discs. At the gap edge, the azimuthally averaged velocities at different disc heights deviate from the Keplerian velocity at similar amplitudes, and its relationship with the planet mass is consistent with that in 2D simulations. After removing the planet, the azimuthally averaged velocity barely changes within the viscous time-scale, and thus the azimuthally averaged velocity structure at the gap edge is due to the gap itself and not directly caused to the planet. Combining both axisymmetric kinematic observations and the residual 'kink' velocity is needed to probe young planets in protoplanetary discs.

Keywords

Accretion; Accretion discs; Astroparticle physics; Dynamo; Instabilities; MHD; Turbulence

Disciplines

Astrophysics and Astronomy | Physical Sciences and Mathematics

File Format

pdf

File Size

5948 KB

Language

English

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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