On the dynamics of pebbles in protoplanetary disks with magnetically-driven winds

TL;DR

This paper develops an analytical model to study how magnetically-driven winds in protoplanetary disks affect pebble production and transport, revealing that strong winds significantly slow core growth by reducing pebble flux.

Contribution

It introduces a novel analytical framework that accounts for differing turbulent coefficients influenced by magnetic winds, exploring their impact on pebble dynamics and planet formation.

Findings

Strong winds reduce pebble flux and delay core growth.

Pebble accretion is unlikely to reach isolation mass under strong wind conditions.

Decreasing wind strength allows faster core growth to pebble isolation mass.

Abstract

We present an analytical model to investigate the production of pebbles and their radial transport through a protoplanetary disk (PPD) with magnetically driven winds. While most of the previous analytical studies in this context assume that the radial turbulent coefficient is equal to the vertical dust diffusion coefficient, in the light of the results of recent numerical simulations, we relax this assumption by adopting effective parametrisations of the turbulent coefficients involved in terms of the strength of the magnetic fields driving the wind. Theoretical studies have already pointed out that even in the absence of winds, these coefficients are not necessarily equal, though its consequences regarding pebble production have not been explored. In this paper, we investigate the evolution of the pebble production line, the radial mass flux of the pebbles and their corresponding surface density as a function of the plasma parameter at the disk midplane. Our analysis explicitly demonstrates that the presence of magnetically-driven winds in a PPD leads to considerable reduction of the rate and duration of the pebble delivery. We show that when the wind is strong, the core growth in mass due to the pebble accretion is so slow that it is unlikely that a core could reach a pebble isolation mass during a PPD lifetime. When the mass of a core reaches this critical value, pebble accretion is halted due to core-driven perturbations in the gas. With decreasing wind strength, however, pebble accretion may, in a shorter time, increase the mass of a core to the pebble isolation mass.