Turbulence and its effect on protostellar disk formation

TL;DR

This study uses simulations to show that turbulence significantly influences the formation and structure of protostellar disks, leading to early Keplerian disks and complex magnetic field configurations.

Contribution

It demonstrates that turbulence causes early disk formation and disrupts classical magnetic and rotational coherence assumptions.

Findings

Keplerian disks form in the Class 0 stage under various conditions.

Mass and angular momentum accrete through narrow, anisotropic channels.

Magnetic fields near disks are highly disordered with reversals up to 1000 AU.

Abstract

We analyse simulations of turbulent, magnetised molecular cloud cores focussing on the formation of Class 0 stage protostellar discs and the physical conditions in their surroundings. We show that for a wide range of initial conditions Keplerian discs are formed in the Class 0 stage already. Furthermore, we show that the accretion of mass and angular momentum in the surroundings of protostellar discs occurs in a highly anisotropic manner, by means of a few narrow accretion channels. The magnetic field structure in the vicinity of the discs is highly disordered, revealing field reversals up to distances of 1000 AU. These findings demonstrate that as soon as even mild turbulent motions are included, the classical disc formation scenario of a coherently rotating environment and a well-ordered magnetic field breaks down.