A Multi-Epoch SMA Study of the HH 211 Protostellar Jet: Jet Motion and Knot Formation

Abstract

HH 211 is a highly collimated jet with a chain of well-defined knots, powered by a nearby young Class 0 protostar. We have used 4 epochs (2004, 2008, 2010, and 2013) of Submillimeter Array (SMA) archive data to study the properties of the HH 211 jet in SiO (J=8-7). The jet shows similar reflection-symmetric wiggle structures in all epochs. The wiggle structures can all be fitted by an orbiting jet source model that includes a position shift due to proper motion of the jet, indicating that the wiggle propagates along the jet axis. Thus, this suggests the wiggle is indeed due to an orbital motion of the jet source. Proper motions of the knots are measured by using the peak positions of the knots in four epochs, and they are roughly the same and independent of the distance from the central source. The mean proper motion of the knots is $\sim$ 0.087 arcsec per year, resulting in a transverse velocity of $\sim$ 114 km s${}^{-1}$, about 30\% lower than that measured before. Knots BK2 and BK3 have a well-defined linear velocity structure, with the fast jet material upstream to the slow jet material. The gradient of the velocity structure decreases from knot BK2 to BK3. In addition, for each knot, the gradient decreases with time, as the knot propagates away from the central source. These results are both expected if the two knots trace internal shocks produced by a small periodical variation in ejection velocity of the jet.

References in corpus (5)

• Submillimeter arcsecond-resolution mapping of the highly collimated protostellar jet HH 211
• Jet Motion, Internal Working Surfaces, and Nested Shells in the Protostellar System HH 212
• The Structure of the Inner HH 34 Jet from Optical Integral Field Spectroscopy
• Magnetic field structure in the Flattened Envelope and Jet in the young protostellar system HH 211
• Velocity-Resolved [Ne III] from X-Ray Irradiated Sz 102 Microjets

Cited by in corpus (20)

• Molecular jets from low-mass young protostellar objects
• The CALYPSO IRAM-PdBI survey of jets from Class 0 protostars. Are jets ubiquitous in young stars ?
• Jets from Young Stars
• 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?
• Episodic accretion constrained by a rich cluster of outflows
• A Pseudodisk Threaded with a Toroidal and Pinched Poloidal Magnetic Field Morphology in the HH 211 Protostellar System
• JWST Observations of Young protoStars (JOYS). HH 211: the textbook case of a protostellar jet and outflow
• Laboratory disruption of scaled astrophysical outflows by a misaligned magnetic field
• 25 AU Angular Resolution Observations of HH 211 with ALMA : Jet Properties and Shock Structures in SiO, CO, and SO
• A study of the wiggle morphology of HH 211 through numerical simulations
• Multi-epoch SMA observations of the L1448C(N) protostellar SiO jet
• Ejection History of the IRAS 04166+2706 Molecular Jet
• Detection of a dense SiO jet in the evolved protostellar phase
• Early Planet Formation in Embedded Disks (eDisk) XVI: An asymmetric dust disk driving a multi-component molecular outflow in the young Class 0 protostar GSS30 IRS3
• Increasing mass-to-flux ratio from the dense core to the protostellar envelope around the Class 0 protostar HH 211
• Herschel spectral-line mapping of the HH211 protostellar system
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Nested Morphological and Kinematic Structures of Outflows Revealed in SiO and CO Emission
• The ALMA Survey of 70 $\mu$m Dark High-mass Clumps in Early Stages (ASHES). XII. Unanchored Forked Stream in the Propagating Path of a Protostellar Outflow
• Modeling of thermal and non-thermal radio emission from HH80-81 jet
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Deriving Inclination Angle and Velocity of the Protostellar Jets from their SiO Knots