On the Dust Signatures Induced by Eccentric Super-Earths in Protoplanetary Disks

TL;DR

This study uses high-resolution hydrodynamical simulations to explore how eccentric super-Earths influence dust structures in protoplanetary disks, revealing mechanisms for gap and ring formation that match observations.

Contribution

It demonstrates that eccentric planets can induce dust gaps and rings at various radii, providing alternative explanations for observed disk features and highlighting the role of disk viscosity.

Findings

Eccentric planets can circularize at large radii, forming dust rings near the circularization radius.

Low disk viscosity enhances dust ring brightness and allows gap formation near pericenter and apocenter.

Eccentric planets can slow dust radial drift, affecting disk evolution and observational signatures.

Abstract

We investigate the impact of a highly eccentric 10 $M_{\rm \oplus}$ (where $M_{\rm \oplus}$ is the Earth mass) planet embedded in a dusty protoplanetary disk on the dust dynamics and its observational implications. By carrying out high-resolution 2D gas and dust two-fluid hydrodynamical simulations, we find that the planet's orbit can be circularized at large radii. After the planet's orbit is circularized, partial gap opening and dust ring formation happen close to the planet's circularization radius, which can explain the observed gaps/rings at the outer region of disks. When the disk mass and viscosity become low, we find that an eccentric planet can even open gaps and produce dust rings close to the pericenter and apocenter radii before its circularization. This offers alternative scenarios for explaining the observed dust rings and gaps in protoplanetary disks. A lower disk viscosity is favored to produce brighter rings in observations. An eccentric planet can also potentially slow down the dust radial drift in the outer region of the disk when the disk viscosity is low ($\alpha \lesssim2\times10^{-4}$) and the circularization is faster than the dust radial drift.