How do giant planetary cores shape the dust disk? HL Tau system

TL;DR

This study uses simulations to explore how multi-planet systems influence dust disk structures, applying models to the HL Tau system to infer planetary masses and disk features based on observed dust distributions.

Contribution

The paper introduces a model of dust evolution in multi-planet systems and applies it to HL Tau, providing new insights into planetary masses and disk features shaping observed dust structures.

Findings

Outer planet influences dust ring formation and vortex development.

Dust ring and gap widths depend on planetary mass and particle stopping times.

Inner and outer planet masses inferred as approximately 0.07 and 0.35 Jupiter masses.

Abstract

We are observing, thanks to ALMA, the dust distribution in the region of active planet formation around young stars. This is a powerful tool to connect observations with theoretical models and improve our understandings of the processes at play. We want to test how a multi-planetary system shapes its birth disk and study the influence of the planetary masses and particle sizes on the final dust distribution. Moreover, we apply our model to the HL Tau system in order to obtain some insights on the physical parameters of the planets that are able to create the observed features. We follow the evolution of a population of dust particles, treated as Lagrangian particles, in two-dimensional, locally isothermal disks where two equal mass planets are present. The planets are kept in fixed orbits and they do not accrete mass. The outer planet plays a major role removing the dust particles in the co-orbital region of the inner planet and forming a particle ring which promotes the development of vortices respect to the single planetary case. The ring and gaps width depends strongly on the planetary mass and particle stopping times, and for the more massive cases the ring clumps in few stable points that are able to collect a high mass fraction. The features observed in the HL Tau system can be explained through the presence of several massive cores that shape the dust disk, where the inner planet(s) should have a mass on the order of 0.07 Jupiter masses and the outer one(s) on the order of 0.35 Jupiter masses. These values can be significantly lower if the disk mass turns out to be less than previously estimated. Decreasing the disk mass by a factor 10 we obtain similar gap widths for planets with a mass of 10 and 20 Earth masses respectively. Although the particle gaps are prominent, the expected gaseous gaps would be barely visible.