On the secular behavior of dust particles in an eccentric protoplanetary disk with an embedded massive gas giant planet

TL;DR

This study models the secular evolution of dust particles in eccentric protoplanetary disks with embedded gas giants, revealing how dust distribution and dynamics are affected by planetary perturbations and gas density.

Contribution

It combines hydrodynamical simulations with secular perturbation theory to analyze dust behavior in eccentric disks with embedded planets, highlighting size-dependent dust-gas coupling effects.

Findings

Dust particles of 0.01 cm to 1 m are well coupled to gas in typical disks.

Dust surface density is enhanced at the apocenter of the disk.

Asymmetric dust distributions can indicate the presence of a massive gas giant.

Abstract

We investigate the dust velocity and spatial distribution in an eccentric protoplanetary disk under the secular gravitational perturbation of an embedded planet of about 5 Jupiter masses. We first employ the FARGO code to obtain the two-dimensional density and velocity profiles of the eccentric gas disk exterior to the gap opened up by the embedded planet in the quasi-steady state. We then apply the secular perturbation theory and incorporate the gas drag to estimate the dust velocity and density on the secular timescale. The dust-to-gas ratio of the unperturbed disk is simply assumed to be 0.01. In our fiducial disk model with the planet at 5 AU, we find that 0.01 cm- to 1 m-sized dust particles are well coupled to the gas. Consequently, the particles behave similarly to the gas and exhibit asymmetric dynamics as a result of eccentric orbits. The dust surface density is enhanced around the apocenter of the disk. However, for the case of a low-density gaseous disk (termed "transition disk" henceforth in this work) harboring the planet at 100 AU, the azimuthal distributions of dust of various sizes can deviate significantly. Overall, the asymmetric structure exhibits a phase correlation between the gas velocity fields and dust density distribution. Therefore, our study potentially provides a reality check as to whether an asymmetric disk gap detected at sub-millimeter and centimeter wavelengths is a signpost of a massive gas giant planet.