The ALMA Survey of 70$\mu$m Dark High-mass Clumps in Early Stages (ASHES) III. A Young Molecular Outflow Driven by a Decelerating Jet

Abstract

We present a spatio-kinematical analysis of the CO~($J$=2$\to$1) line emission, observed with the Atacama Large Millimter/submillimter Array (ALMA), of the outflow associated with the most massive core, ALMA1, in the 70 $\mu$m dark clump G010.991$-$00.082. The position-velocity (P-V) diagram of the molecular outflow exhibits a peculiar $\mathsf{S}$-shaped morphology that has not been seen in any other star forming region. We propose a spatio-kinematical model for the bipolar molecular outflow that consists of a decelerating high-velocity component surrounded by a slower component whose velocity increases with distance from the central source. The physical interpretation of the model is in terms of a jet that decelerates as it entrains material from the ambient medium, which has been predicted by calculations and numerical simulations of molecular outflows in the past. One side of the outflow is shorter and shows a stronger deceleration, suggesting that the medium through which the jet moves is significantly inhomogeneous. The age of the outflow is estimated to be $\tau$$\approx$1300 years, after correction for a mean inclination of the system of $\approx$57${}^{\circ }$.

15 pages, 7 figures. Accepted for publication in ApJ

References in corpus (19)

• The ALMA Survey of 70 $\mu$m dark High-mass clumps in Early Stages (ASHES). I. Pilot Survey: Clump Fragmentation
• Fragmentation of Molecular Clumps and Formation of Protocluster
• Spitzer IRAC and MIPS Imaging of Clusters and Outflows in 9 High-mass Star Forming Regions
• Molecular jets from low-mass young protostellar objects
• A Census of Large-Scale ($\ge$ 10 pc), Velocity-Coherent, Dense Filaments in the Northern Galactic Plane: Automated Identification Using Minimum Spanning Tree
• ALMA observations of fragmentation, sub-structure, and protostars in high-mass starless clump candidates
• The ALMA Survey of 70 $\mu \mathrm{m}$ Dark High-mass Clumps in Early Stages (ASHES). II: Molecular Outflows in the Extreme Early Stages of Protocluster Formation
• The Role of Outflows, Radiation Pressure, and Magnetic Fields in Massive Star Formation
• Formation of Massive Protostellar Clusters -- Observations of Massive 70 $\mu$m Dark Molecular Clouds
• Methanol Maser Associated Outflows: Detection statistics and properties
• Massive and low-mass protostars in massive "starless" cores
• Episodic accretion constrained by a rich cluster of outflows
• Characterizing the properties of cluster precursors in the MALT90 survey
• Widespread Molecular Outflows in the Infrared Dark Cloud G28.37+0.07: Indications of Orthogonal Outflow-Filament Alignment
• ALMA Observations of the Water Fountain Pre-Planetary Nebula IRAS 16342-3814: High-velocity bipolar jets and an Expanding Torus
• A SiO J = 5 - 4 Survey Toward Massive Star Formation Regions
• Initial Fragmentation in the Infrared Dark Cloud G28.53-0.25
• Shaping the envelope of the asymptotic giant branch star W43A with a collimated fast jet
• G5.89: An Explosive Outflow Powered by a Proto-Stellar Merger?

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• The ALMA Survey of 70 $\mu$m Dark High-mass Clumps in Early Stages (ASHES). IV. Star formation signatures in G023.477
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• The ALMA Survey of 70 $\mu$m Dark High-mass Clumps in Early Stages (ASHES). V. Deuterated Molecules in the 70 $\mu$m dark IRDC G14.492-00.139
• The Role of Magnetic Fields in the Formation of the Filamentary Infrared Dark Cloud G11.11-0.12
• 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
• The symbiotic and bipolar nebula M2-9: Morphological variability of the collimated ionized wind arising from the core
• Origins of the shocks in high-mass starless clump candidates