The Magnetic Field in the Class 0 Protostellar Disk of L1527

TL;DR

This study uses high-resolution dust polarization observations of the L1527 protostar to analyze its magnetic field structure, suggesting magnetorotational instability dominates angular momentum transport and that magnetic field alignment influences early disk formation.

Contribution

It provides the first detailed magnetic field morphology of a Class 0 protostellar disk at subarcsecond resolution, highlighting the role of magnetic field orientation in disk development.

Findings

Magnetic field is predominantly toroidal with no significant vertical component.

Angular momentum transport is likely driven by magnetorotational instability.

Disks larger than 30 AU tend to be in systems with misaligned magnetic fields.

Abstract

We present subarcsecond (~0.35") resolved observations of the 1.3 mm dust polarization from the edge-on circumstellar disk around the Class 0 protostar L1527. The inferred magnetic field is consistent with a dominantly toroidal morphology; there is no significantly detected vertical poloidal component to which observations of an edge-on disk are most sensitive. This suggests that angular momentum transport in Class 0 protostars (when large amounts of material are fed down to the disk from the envelope and accreted onto the protostar) is driven mainly by magnetorotational instability rather than magnetocentrifugal winds at 50 AU scales. In addition, with the data to date there is an early, tentative trend that R>30 AU disks have so far been found in Class 0 systems with average magnetic fields on the 1000 AU scale strongly misaligned with the rotation axis. The absence of such a disk in the aligned case could be due to efficient magnetic braking that disrupts disk formation. If this is the case, this implies that candidate Class 0 disk systems could be identified by the average magnetic field direction at ~1000 AU spatial scales.