The Hourglass-shaped Magnetic Fields and Dust Filaments in the HH 211 Protostellar Envelope

Abstract Magnetic fields influence the structure and evolution of protostellar systems; thus, understanding their role is essential for probing the earliest stages of star formation. We present Atacama Large Millimeter/submillimeter Array Band 3 and 6 polarized continuum observations at ∼0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>″</mml:mtext> </mml:mrow> </mml:mover> </mml:math> 5 resolution toward the Class 0 protostellar system HH 211. Three dust filaments (∼4000 au in length) are found in the HH 211 protostellar envelope, two of which are aligned with core-scale (∼10,000 au) magnetic fields detected by previous James Clerk Maxwell Telescope observations. This result suggests that the formation of the dust filaments may be influenced by magnetic fields. In the inner envelope (∼1000 au), we detect a clear hourglass-shaped magnetic field morphology near the protostar and toroidal fields along the outflow directions. We also estimate the line-of-sight averaged temperature and column density distributions in the inner envelope and find that the temperature is higher in the east, while the column density is enhanced in the southern and western regions. The southern dense regions of the inner envelope may trace either outflow cavity walls, due to their alignment with the outflow, or possible infalling channels in the midplane, given the close correspondence between the observed magnetic fields and the predicted infall trajectories.