Artículo de revista
ALMA Reveals Sequential High-mass Star Formation in the G9.62+0.19 Complex
Fecha
2017Registro en:
Astrophysical Journal, 2017 Vol. 849 (1)
10.3847/1538-4357/aa8d73
Autor
Liu, Tie
Lacy, John
Li, Pak Shing
Wang, Ke
Qin, Sheng-Li
Zhang, Qizhou
Kim, Kee-Tae
Garay Brignardello, Guido
Wu, Yuefang
Mardones, Diego
Zhu, Qingfeng
Tatematsu, Ken'ichi
Hirota, Tomoya
Ren, Zhiyuan
Liu, Sheng-Yuan
Chen, Huei-Ru
Su, Yu-Nung
Li, Di
Institución
Resumen
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-circle dot, 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.