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High-mass star formation through filamentary collapse and clump-fed accretion in G22

Citation

Yuan, J and Li, J-Z and Wu, Y and Ellingsen, SP and Henkel, C and Wang, K and Liu, T and Liu, H-L and Zavagno, A and Ren, Z and Huang, Y-F, High-mass star formation through filamentary collapse and clump-fed accretion in G22, Astrophysical Journal, 852, (1) Article 12. ISSN 0004-637X (2018) [Refereed Article]


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Copyright 2017 The American Astronomical Society

DOI: doi:10.3847/1538-4357/aa9d40

Abstract

How mass is accumulated from cloud-scale down to individual stars is a key open question in understanding high-mass star formation. Here, we present the mass accumulation process in a hub-filament cloud G22 that is composed of four supercritical filaments. Velocity gradients detected along three filaments indicate that they are collapsing with a total mass infall rate of about 440 M Myr−1, suggesting the hub mass would be doubled in six free-fall times, adding up to ~2 Myr. A fraction of the masses in the central clumps C1 and C2 can be accounted for through large-scale filamentary collapse. Ubiquitous blue profiles in HCO+ (3–2) and 13CO (3–2) spectra suggest a clump-scale collapse scenario in the most massive and densest clump C1. The estimated infall velocity and mass infall rate are 0.31 km s−1 and 7.2 × 10−4 M yr−1, respectively. In clump C1, a hot molecular core (SMA1) is revealed by the Submillimeter Array observations and an outflow-driving high-mass protostar is located at the center of SMA1. The mass of the protostar is estimated to be 11–15 M and it is still growing with an accretion rate of 7 × 10−5 M yr−1. The coexistent infall in filaments, clump C1, and the central hot core in G22 suggests that pre-assembled mass reservoirs (i.e., high-mass starless cores) may not be required to form high-mass stars. In the course of high-mass star formation, the central protostar, the core, and the clump can simultaneously grow in mass via core-fed/disk accretion, clump-fed accretion, and filamentary/cloud collapse.

Item Details

Item Type:Refereed Article
Keywords:ISM: clouds, ISM: individual objects (G22), ISM: kinematics and dynamics, stars: formation, stars: massive
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Galactic Astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
UTAS Author:Ellingsen, SP (Professor Simon Ellingsen)
ID Code:123718
Year Published:2018
Web of Science® Times Cited:5
Deposited By:Mathematics and Physics
Deposited On:2018-01-22
Last Modified:2019-02-27
Downloads:31 View Download Statistics

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