The ALMA Survey of 70 mu m Dark High-mass Clumps in Early Stages (ASHES). IV. Star Formation Signatures in G023.477
Journal article, 2021
With a mass of similar to 1000 M (circle dot) and a surface density of similar to 0.5 g cm(-2), G023.477+0.114, also known as IRDC 18310-4, is an infrared dark cloud (IRDC) that has the potential to form high-mass stars and has been recognized as a promising prestellar clump candidate. To characterize the early stages of high-mass star formation, we have observed G023.477+0.114 as part of the Atacama Large Millimeter/submillimeter Array (ALMA) Survey of 70 mu m Dark High-mass Clumps in Early Stages. We have conducted similar to 1.'' 2 resolution observations with ALMA at 1.3 mm in dust continuum and molecular line emission. We have identified 11 cores, whose masses range from 1.1 to 19.0 M (circle dot). Ignoring magnetic fields, the virial parameters of the cores are below unity, implying that the cores are gravitationally bound. However, when magnetic fields are included, the prestellar cores are close to virial equilibrium, while the protostellar cores remain sub-virialized. Star formation activity has already started in this clump. Four collimated outflows are detected in CO and SiO. H2CO and CH3OH emission coincide with the high-velocity components seen in the CO and SiO emission. The outflows are randomly oriented for the natal filament and the magnetic field. The position-velocity diagrams suggest that episodic mass ejection has already begun even in this very early phase of protostellar formation. The masses of the identified cores are comparable to the expected maximum stellar mass that this IRDC could form (8-19 M (circle dot)). We explore two possibilities on how IRDC G023.477+0.114 could eventually form high-mass stars in the context of theoretical scenarios.
Author
Kaho Morii
University of Tokyo
National Institutes of Natural Sciences
Patricio Sanhueza
National Institutes of Natural Sciences
The Graduate University for Advanced Studies (SOKENDAI)
Fumitaka Nakamura
The Graduate University for Advanced Studies (SOKENDAI)
University of Tokyo
National Institutes of Natural Sciences
James M. Jackson
NASA Ames Research Center
Shanghuo Li
Korea Astronomy and Space Science Institute
Henrik Beuther
Max Planck Society
Qizhou Zhang
Harvard-Smithsonian Center for Astrophysics
Siyi Feng
Xiamen University
Daniel Tafoya
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Andres E. Guzman
National Institutes of Natural Sciences
Natsuko Izumi
Academia Sinica
Takeshi Sakai
University of Electro-Communications
Xing Lu
National Institutes of Natural Sciences
Ken'ichi Tatematsu
The Graduate University for Advanced Studies (SOKENDAI)
National Institutes of Natural Sciences
Satoshi Ohashi
RIKEN
Andrea Silva
University of Tokyo
Fernando A. Olguin
National Tsing Hua University
Yanett Contreras
Leiden University
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 923 2 147Subject Categories
Astronomy, Astrophysics and Cosmology
Fusion, Plasma and Space Physics
Condensed Matter Physics
DOI
10.3847/1538-4357/ac2365