A Pseudodisk Threaded with a Toroidal and Pinched Poloidal Magnetic Field Morphology in the HH 211 Protostellar System

Abstract

The HH 211 protostellar system is currently the youngest Class 0 system found with a rotating disk. We have mapped it at ~ 50 au (0.16") resolution, studying its magnetic field morphology with dust polarization in continuum at 232 and 358 GHz and its kinematics in C18O J=2-1 line. A flattened envelope extending out to ~ 400 au from the disk is detected in the continuum and C18O, slightly misaligned with the disk by 8 degree. It is spiraling inwards and expected to transform into a rotating disk at ~ 20 au, consistent with the disk radius estimated before. It appears to have a constant specific angular momentum and itself can result from an inside-out collapse of an extended envelope detected before in NH${}_3$. In the flattened envelope, the polarization is mainly due to the magnetically aligned dust grains, inferring a highly pinched poloidal field morphology there. Thus, both the kinematics and field morphology support that the flattened envelope is a pseudodisk formed as the infalling gas is guided by the field lines to the equatorial plane. Interestingly, a point symmetric polarization distribution is also seen in the flattened envelope, implying that the pinched field lines also have a significant toroidal component generated by the rotation. No significant loss of angular momentum and thus no clear magnetic braking are detected in the flattened envelope around the disk probably because of the large misalignment between the axis of the rotation and the axis of the magnetic field in the cloud core.

28 pages, 9 figures, accepted by ApJ

References in corpus (14)

• Magnetic Braking and Protostellar Disk Formation: The Ideal MHD Limit
• Formation of a Keplerian disk in the infalling envelope around L1527 IRS: transformation from infalling motions to Kepler motions
• The evidence of radio polarization induced by the radiative grain alignment and self-scattering of dust grains in a protoplanetary disk
• ALMA Reveals Transition of Polarization Pattern with Wavelength in HL Tau's Disk
• Formation and Atmosphere of Complex Organic Molecules of the HH 212 Protostellar Disk
• A Sub-arcsecond Survey Toward Class 0 Protostars in Perseus: Searching for Signatures of Protostellar Disks
• ALMA Results of the Pseudodisk, Rotating disk, and Jet in Continuum and HCO+ in the Protostellar System HH 212
• Submillimeter arcsecond-resolution mapping of the highly collimated protostellar jet HH 211
• On the Role of Pseudodisk Warping and Reconnection in Protostellar Disk Formation in Turbulent Magnetized Cores
• Origin of Misalignments: Protostellar Jet, Outflow, Circumstellar Disc, and Magnetic Field
• Revealing the dust grain size in the inner envelope of the Class I protostar Per-emb-50
• Magnetic field structure in the Flattened Envelope and Jet in the young protostellar system HH 211
• JCMT POL-2 and ALMA polarimetric observations of 6000-100 au scales in the protostar B335: linking magnetic field and gas kinematics in observations and MHD simulations
• Time Evolution of 3D Disk Formation with Misaligned Magnetic Field and Rotation Axes

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• What Produces Dust Polarization in the HH 212 Protostellar Disk at 878 μm: Dust Self-Scattering or Dichroic Extinction?
• The JCMT BISTRO survey: alignment between outflows and magnetic fields in dense cores/clumps
• 25 AU Angular Resolution Observations of HH 211 with ALMA : Jet Properties and Shock Structures in SiO, CO, and SO
• The Infall Motion in the Low-Mass Protostellar Binary NGC 1333 IRAS 4A1/4A2
• Magnetic Spirals in Accretion Flows Originated from Misaligned Magnetic Field
• Simulations of the isothermal collapse of magnetic rotating protostellar clouds
• Primary disks and their observational appearance in collapsing magnetic rotating protostellar clouds
• Effects of magnetic field orientations in dense cores on gas kinematics in protostellar envelopes