Oral Presentation

Sequential High-mass Star Formation in the G9.62+0.19 Complex

Author(s): Tie Liu (SHAO)

Presenter: Tie Liu (Shanghai Astronomical Observatory)

Stellar feedback from high-mass stars (e.g., H II regions) can strongly influence the surrounding interstellar medium and regulate star formation. Our SMA and 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 dense cores (MM1-MM12) detected by SMA and 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. Five cores (MM1, MM3, MM5, MM9, MM10) are massive starless core candidates whose masses are estimated to be larger than 25 M ☉, 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. I will also present some preliminary results from our SMA and JCMT polarization observations toward this region, which reveal magnetic fields compressed by the expanding HII regions.