Effect of Angular Momentum Alignment and Strong Magnetic Fields on the Formation of Protostellar Disks

TL;DR

This study uses high-resolution simulations to explore how turbulence, magnetic fields, and their alignment influence the formation of protostellar disks in magnetized molecular clouds, highlighting the importance of turbulence-induced misalignment.

Contribution

It demonstrates that turbulence-induced misalignment is essential for protostellar disk formation in magnetized environments, especially when turbulence is aligned with magnetic fields.

Findings

Aligned turbulence prevents disk formation regardless of turbulent energy.

Misalignment between angular momentum and magnetic fields promotes disk formation.

Turbulence plays a critical role in overcoming magnetic braking.

Abstract

Star forming molecular clouds are observed to be both highly magnetized and turbulent. Consequently the formation of protostellar disks is largely dependent on the complex interaction between gravity, magnetic fields, and turbulence. Studies of non-turbulent protostellar disk formation with realistic magnetic fields have shown that these fields are efficient in removing angular momentum from the forming disks, preventing their formation. However, once turbulence is included, disks can form in even highly magnetized clouds, although the precise mechanism remains uncertain. Here we present several high resolution simulations of turbulent, realistically magnetized, high-mass molecular clouds with both aligned and random turbulence to study the role that turbulence, misalignment, and magnetic fields have on the formation of protostellar disks. We find that when the turbulence is artificially aligned so that the angular momentum is parallel to the initial uniform field, no rotationally supported disks are formed, regardless of the initial turbulent energy. We conclude that turbulence and the associated misalignment between the angular momentum and the magnetic field are crucial in the formation of protostellar disks in the presence of realistic magnetic fields.