Angular momentum loss in the envelope-disk transition region of HH 111 protostellar system: evidence for magnetic braking?

Abstract

HH 111 is a Class I protostellar system at a distance of ~ 400 pc, with the central source VLA 1 associated with a rotating disk deeply embedded in a flattened envelope. Here we present the observations of this system at ~ 0.6" (240 AU) resolution in C18O (J=2-1) and 230 GHz continuum obtained with Atacama Large Millimeter/Submillimeter Array, and in SO obtained with Submillimeter Array. The observations show for the first time how a Keplerian rotating disk can be formed inside a flattened envelope. The flattened envelope is detected in C18O, extending out to >~ 2400 AU from the VLA 1 source. It has a differential rotation, with the outer part (>~ 2000 AU) better described by a rotation that has constant specific angular momentum and the innermost part (<~ 160 AU) by a Keplerian rotation. The rotationally supported disk is therefore relatively compact in this system, which is consistent with the dust continuum observations. Most interestingly, if the flow is in steady state, there is a substantial drop in specific angular momentum in the envelope-disk transition region from 2000 AU to 160 AU, by a factor of ~ 3. Such a decrease is not expected outside a disk formed from simple hydrodynamic core collapse, but can happen naturally if the core is significantly magnetized, because magnetic fields can be trapped in the transition region outside the disk by the ram pressure of the protostellar accretion flow, which can lead to efficient magnetic braking. In addition, SO shock emission is detected around the outer radius of the disk and could trace an accretion shock around the disk.

References in corpus (6)

• Planck intermediate results. XIX. An overview of the polarized thermal emission from Galactic dust
• Magnetic Braking and Protostellar Disk Formation: The Ideal MHD Limit
• Magnetic Fields in Dark Cloud Cores: Arecibo OH Zeeman Observations
• Formation of a Keplerian disk in the infalling envelope around L1527 IRS: transformation from infalling motions to Kepler motions
• ALMA Results of the Pseudodisk, Rotating disk, and Jet in Continuum and HCO+ in the Protostellar System HH 212
• High Angular Resolution Observations at 7-mm of the Core of the Quadrupolar HH 111/121 Outflow

Cited by in corpus (26)

• On the diversity and statistical properties of protostellar discs
• Characterizing young protostellar disks with the CALYPSO IRAM-PdBI survey: large Class 0 disks are rare
• Signs of Early-Stage Disk Growth Revealed with ALMA
• Formation and Atmosphere of Complex Organic Molecules of the HH 212 Protostellar Disk
• Molecular jets from low-mass young protostellar objects
• ALMA Observations of the Protostar L1527 IRS: Probing Details of the Disk and the Envelope Structures
• Characterizing magnetic field morphologies in three Serpens protostellar cores with ALMA
• ALMA Dust Polarization Observations of Two Young Edge-on Protostellar Disks
• Searching for kinematic evidence of Keplerian disks around Class 0 protostars with CALYPSO
• A 100 au-Wide Bipolar Rotating Shell Emanating From The HH 212Protostellar Disk: A Disk Wind?
• ALMA observations of the very young Class 0 protostellar system HH 211-mms: a 30-au dusty disk with a disk-wind traced by SO?
• Disk structure around the Class I protostar L1489 IRS revealed by ALMA: a warped disk system
• The JCMT BISTRO survey: alignment between outflows and magnetic fields in dense cores/clumps
• A Pseudodisk Threaded with a Toroidal and Pinched Poloidal Magnetic Field Morphology in the HH 211 Protostellar System
• Water and interstellar complex organics associated with the HH 212 protostellar disc - On disc atmospheres, disc winds, and accretion shocks
• ALMA observations of the protostellar disk around the VeLLO IRAS 16253-2429
• Sub-arcsecond Kinematic Structure of the Outflow in the Vicinity of the Protostar in L483
• A Detailed View of the Circumstellar Environment and Disk of the Forming O-star AFGL 4176
• Constraint on ion-neutral drift velocity in the Class 0 protostar B335 from ALMA observations
• 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
• Probing jets from young embedded sources: clues from HST near-IR [Fe II] images
• Very Large Array Ammonia Observations of the HH 111/HH 121 Protostellar System: a Detection of a New Source With a Peculiar Chemistry
• Models for velocity decrease in HH34
• The Rotation Dip in the Envelope-Disk Transition of HH 111: Evidence for Magnetic Braking
• Modelling the Break in the Specific Angular Momentum within the Envelope-Disk Transition Zone
• Effects of magnetic field orientations in dense cores on gas kinematics in protostellar envelopes