A Dust-Trapping Ring in the Planet-Hosting Disk of Elias 2-24

TL;DR

This study provides high-resolution evidence of dust trapping in a bright ring of the Elias 2-24 protoplanetary disk, revealing insights into dust dynamics, turbulence, and potential planet formation processes.

Contribution

It offers the first detailed analysis of dust trapping and grain size distribution in Elias 2-24's disk using high-resolution ALMA data, constraining turbulence and gas-to-dust ratios.

Findings

Larger grains are more efficiently trapped in the ring.

Turbulence parameter constrained between 8e-4 and 0.03.

Disk mass estimated at approximately 1.38e-3 solar masses.

Abstract

Rings and gaps are among the most widely observed forms of substructure in protoplanetary disks. A gap-ring pair may be formed when a planet carves a gap in the disk, which produces a local pressure maximum following the gap that traps inwardly drifting dust grains and appears as a bright ring due to the enhanced dust density. A dust-trapping ring would provide a promising environment for solid growth and possibly planetesimal production via the streaming instability. We present evidence of dust trapping in the bright ring of the planet-hosting disk Elias 2-24, from the analysis of 1.3 mm and 3 mm ALMA observations at high spatial resolution (0.029 arcsec, 4.0 au). We leverage the high spatial resolution to demonstrate that larger grains are more efficiently trapped and place constraints on the local turbulence ($8 \times 10^{-4} < \alpha_\mathrm{turb} < 0.03$) and the gas-to-dust ratio ($\Sigma_g / \Sigma_d < 30$) in the ring. Using a scattering-included marginal probability analysis we measure a total dust disk mass of $M_\mathrm{dust} = 13.8^{+0.7}_{-0.5} \times 10^{-4} \ M_\odot$. We also show that at the orbital radius of the proposed perturber, the gap is cleared of material down to a flux contrast of 10$^{-3}$ of the peak flux in the disk.