High-mass Star Formation through Filamentary Collapse and Clump-fed Accretion in G22

High-mass Star Formation through Filamentary Collapse and Clump-fed Accretion in G22

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 fil...

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Bibliographic Details
Published in:Astrophysical journal. Letters 2018-01, Vol.852 (1), p.12
Main Authors: Yuan, Jinghua, Li, Jin-Zeng, Wu, Yuefang, Ellingsen, Simon P., Henkel, Christian, Wang, Ke, Liu, Tie, Liu, Hong-Li, Zavagno, Annie, Ren, Zhiyuan, Huang, Ya-Fang
Format: Article
Language:eng
Subjects:
Accretion
Accretion disks
Astrophysics
Clouds
Clumps
Collapse
Filaments
ISM: clouds
ISM: individual objects (G22)
ISM: kinematics and dynamics
Massive stars
Sciences of the Universe
Star & galaxy formation
Star formation
Stars & galaxies
stars: formation
stars: massive
Velocity
Velocity gradient
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Summary: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.
ISSN:0004-637X
2041-8205
1538-4357
2041-8213