Vertical Shear Instability in Thermally-Stratified Protoplanetary Disks: II. Hydrodynamic Simulations and Observability

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Yun, Han-Gyeol, Kim, Woong-Tae, Bae, Jaehan, Han, Cheongho
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866912154464026624
author Yun, Han-Gyeol
Kim, Woong-Tae
Bae, Jaehan
Han, Cheongho
author_facet Yun, Han-Gyeol
Kim, Woong-Tae
Bae, Jaehan
Han, Cheongho
contents We conduct three-dimensional hydrodynamic simulations to investigate the nonlinear outcomes and observability of vertical shear instability (VSI) in protoplanetary disks. Our models include both vertically isothermal and thermally stratified disks, with the latter representing realistic conditions featuring a hotter atmosphere above the midplane. We find that the VSI grows more rapidly and becomes stronger in thermally stratified disks due to enhanced shear, resulting in higher levels of turbulence. At saturation, the turbulence stress reaches $α_{Rϕ}\gtrsim 10^{-3}$, more than an order of magnitude stronger than the isothermal case. The saturated turbulence is more pronounced near the disk surfaces than at the midplane. On synthetic velocity residual maps, obtained by subtracting the Keplerian rotational velocity, perturbations driven by the VSI manifest as axisymmetric rings in isothermal disks and as ring segments in thermally stratified disks. The latter are visible at disk inclinations as high as $45^\circ$ in thermally stratified disks. The amplitudes of these residual velocities range from $\sim 50$ to $\sim100$ $\mathrm{m\ s}^{-1}$ at a $20^\circ$ inclination, with larger values corresponding to greater thermal stratification. The magnitude of the observed velocity residual increases with the optical depth of the tracer used, as optically thick lines probe the regions near the disk surfaces.
format Preprint
id arxiv_https___arxiv_org_abs_2412_09930
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Vertical Shear Instability in Thermally-Stratified Protoplanetary Disks: II. Hydrodynamic Simulations and Observability
Yun, Han-Gyeol
Kim, Woong-Tae
Bae, Jaehan
Han, Cheongho
Earth and Planetary Astrophysics
We conduct three-dimensional hydrodynamic simulations to investigate the nonlinear outcomes and observability of vertical shear instability (VSI) in protoplanetary disks. Our models include both vertically isothermal and thermally stratified disks, with the latter representing realistic conditions featuring a hotter atmosphere above the midplane. We find that the VSI grows more rapidly and becomes stronger in thermally stratified disks due to enhanced shear, resulting in higher levels of turbulence. At saturation, the turbulence stress reaches $α_{Rϕ}\gtrsim 10^{-3}$, more than an order of magnitude stronger than the isothermal case. The saturated turbulence is more pronounced near the disk surfaces than at the midplane. On synthetic velocity residual maps, obtained by subtracting the Keplerian rotational velocity, perturbations driven by the VSI manifest as axisymmetric rings in isothermal disks and as ring segments in thermally stratified disks. The latter are visible at disk inclinations as high as $45^\circ$ in thermally stratified disks. The amplitudes of these residual velocities range from $\sim 50$ to $\sim100$ $\mathrm{m\ s}^{-1}$ at a $20^\circ$ inclination, with larger values corresponding to greater thermal stratification. The magnitude of the observed velocity residual increases with the optical depth of the tracer used, as optically thick lines probe the regions near the disk surfaces.
title Vertical Shear Instability in Thermally-Stratified Protoplanetary Disks: II. Hydrodynamic Simulations and Observability
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2412.09930