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Title: ALMA Reveals Sequential High-mass Star Formation in the G9.62+0.19 Complex

Abstract

Stellar feedback from high-mass stars (e.g., H ii regions) can strongly influence the surrounding interstellar medium and regulate star formation. Our new ALMA observations reveal sequential high-mass star formation taking place within one subvirial filamentary clump (the G9.62 clump) in the G9.62+0.19 complex. The 12 dense cores (MM1–MM12) detected by ALMA are at very different evolutionary stages, from the starless core phase to the UC H ii region phase. Three dense cores (MM6, MM7/G, MM8/F) are associated with outflows. The mass–velocity diagrams of the outflows associated with MM7/G and MM8/F can be well-fit by broken power laws. The mass–velocity diagram of the SiO outflow associated with MM8/F breaks much earlier than other outflow tracers (e.g., CO, SO, CS, HCN), suggesting that SiO traces newly shocked gas, while the other molecular lines (e.g., CO, SO, CS, HCN) mainly trace the ambient gas continuously entrained by outflow jets. Five cores (MM1, MM3, MM5, MM9, MM10) are massive starless core candidates whose masses are estimated to be larger than 25 M {sub ☉}, assuming a dust temperature of ≤20 K. The shocks from the expanding H ii regions (“B” and “C”) to the west may have a great impact on the G9.62 clumpmore » by compressing it into a filament and inducing core collapse successively, leading to sequential star formation. Our findings suggest that stellar feedback from H ii regions may enhance the star formation efficiency and suppress low-mass star formation in adjacent pre-existing massive clumps.« less

Authors:
;  [1];  [2];  [3];  [4];  [5];  [6]; ;  [7];  [8];  [9]; ;  [10]; ;  [11]; ; ;  [12]
  1. Korea Astronomy and Space Science Institute 776, Daedeokdae-ro, Yuseong-gu, Daejeon, Korea 34055 (Korea, Republic of)
  2. Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)
  3. Astronomy Department, University of California, Berkeley, CA 94720 (United States)
  4. European Southern Observatory, Karl-Schwarzschild-Str.2, D-85748 Garching bei München (Germany)
  5. Department of Astronomy, Yunnan University, and Key Laboratory of Astroparticle Physics of Yunnan Province, Kunming, 650091 (China)
  6. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  7. Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile)
  8. Department of Astronomy, Peking University, Beijing 100871 (China)
  9. Astronomy Department, University of Science and Technology, Chinese Academy of Sciences, Hefei 210008 (China)
  10. National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
  11. National Astronomical Observatories, Chinese Academy of Science, A20 Datun Road, Chaoyang District, Beijing 100012 (China)
  12. Academia Sinica, Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China)
Publication Date:
OSTI Identifier:
22679718
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 849; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION SPECTRA; CARBON MONOXIDE; COSMIC DUST; EFFICIENCY; FEEDBACK; FILAMENTS; INTERSTELLAR SPACE; MASS; SILICON OXIDES; STARS; VELOCITY

Citation Formats

Liu, Tie, Kim, Kee-Tae, Lacy, John, Li, Pak Shing, Wang, Ke, Qin, Sheng-Li, Zhang, Qizhou, Garay, Guido, Mardones, Diego, Wu, Yuefang, Zhu, Qingfeng, Tatematsu, Ken’ichi, Hirota, Tomoya, Ren, Zhiyuan, Li, Di, Liu, Sheng-Yuan, Chen, Huei-Ru, and Su, Yu-Nung, E-mail: liutiepku@gmail.com. ALMA Reveals Sequential High-mass Star Formation in the G9.62+0.19 Complex. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA8D73.
Liu, Tie, Kim, Kee-Tae, Lacy, John, Li, Pak Shing, Wang, Ke, Qin, Sheng-Li, Zhang, Qizhou, Garay, Guido, Mardones, Diego, Wu, Yuefang, Zhu, Qingfeng, Tatematsu, Ken’ichi, Hirota, Tomoya, Ren, Zhiyuan, Li, Di, Liu, Sheng-Yuan, Chen, Huei-Ru, & Su, Yu-Nung, E-mail: liutiepku@gmail.com. ALMA Reveals Sequential High-mass Star Formation in the G9.62+0.19 Complex. United States. doi:10.3847/1538-4357/AA8D73.
Liu, Tie, Kim, Kee-Tae, Lacy, John, Li, Pak Shing, Wang, Ke, Qin, Sheng-Li, Zhang, Qizhou, Garay, Guido, Mardones, Diego, Wu, Yuefang, Zhu, Qingfeng, Tatematsu, Ken’ichi, Hirota, Tomoya, Ren, Zhiyuan, Li, Di, Liu, Sheng-Yuan, Chen, Huei-Ru, and Su, Yu-Nung, E-mail: liutiepku@gmail.com. Wed . "ALMA Reveals Sequential High-mass Star Formation in the G9.62+0.19 Complex". United States. doi:10.3847/1538-4357/AA8D73.
@article{osti_22679718,
title = {ALMA Reveals Sequential High-mass Star Formation in the G9.62+0.19 Complex},
author = {Liu, Tie and Kim, Kee-Tae and Lacy, John and Li, Pak Shing and Wang, Ke and Qin, Sheng-Li and Zhang, Qizhou and Garay, Guido and Mardones, Diego and Wu, Yuefang and Zhu, Qingfeng and Tatematsu, Ken’ichi and Hirota, Tomoya and Ren, Zhiyuan and Li, Di and Liu, Sheng-Yuan and Chen, Huei-Ru and Su, Yu-Nung, E-mail: liutiepku@gmail.com},
abstractNote = {Stellar feedback from high-mass stars (e.g., H ii regions) can strongly influence the surrounding interstellar medium and regulate star formation. Our new ALMA observations reveal sequential high-mass star formation taking place within one subvirial filamentary clump (the G9.62 clump) in the G9.62+0.19 complex. The 12 dense cores (MM1–MM12) detected by ALMA are at very different evolutionary stages, from the starless core phase to the UC H ii region phase. Three dense cores (MM6, MM7/G, MM8/F) are associated with outflows. The mass–velocity diagrams of the outflows associated with MM7/G and MM8/F can be well-fit by broken power laws. The mass–velocity diagram of the SiO outflow associated with MM8/F breaks much earlier than other outflow tracers (e.g., CO, SO, CS, HCN), suggesting that SiO traces newly shocked gas, while the other molecular lines (e.g., CO, SO, CS, HCN) mainly trace the ambient gas continuously entrained by outflow jets. Five cores (MM1, MM3, MM5, MM9, MM10) are massive starless core candidates whose masses are estimated to be larger than 25 M {sub ☉}, assuming a dust temperature of ≤20 K. The shocks from the expanding H ii regions (“B” and “C”) to the west may have a great impact on the G9.62 clump by compressing it into a filament and inducing core collapse successively, leading to sequential star formation. Our findings suggest that stellar feedback from H ii regions may enhance the star formation efficiency and suppress low-mass star formation in adjacent pre-existing massive clumps.},
doi = {10.3847/1538-4357/AA8D73},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 849,
place = {United States},
year = {2017},
month = {11}
}