Previous observations have revealed an accretion disk and outflow motion in the high-mass starforming region G192.16–3.84, but collapse has not been reported before. Here we present molecular line and continuum obser...Previous observations have revealed an accretion disk and outflow motion in the high-mass starforming region G192.16–3.84, but collapse has not been reported before. Here we present molecular line and continuum observations toward the massive core G192.16–3.84 with the Submillimeter Array. C18 O(2–1) and HCO+(3–2) lines show pronounced blue profiles, indicating gas infalling in this region. This is the first time that infall motion has been reported in the G192.16–3.84 core. Two-layer model fitting gives infall velocities of 2.0±0.2 and 2.8±0.1 km s-1. Assuming that the cloud core follows a power-law density profile(ρ∝ r1.5), the corresponding mass infall rates are(4.7±1.7)×10-3 and(6.6±2.1)×10-3 M⊙yr-1 for C18 O(2–1) and HCO+(3–2), respectively. The derived infall rates are in agreement with the turbulent core model and those in other high-mass star-forming regions, suggesting that high accretion rate is a general requirement for forming a massive star.展开更多
For the first time, the OMC-2/3 region was mapped in C2H （1–0）, HC3N （10–9） and HNC （1–0） lines. In general, the emissions from all the three molecular species reveal an extended filamentary structure. The di...For the first time, the OMC-2/3 region was mapped in C2H （1–0）, HC3N （10–9） and HNC （1–0） lines. In general, the emissions from all the three molecular species reveal an extended filamentary structure. The distribution of C2H cores almost follows that of the 1300μm condensations, which might suggest that C2H is a good tracer to study the core structure of molecular clouds. The core masses traced by HNC are rather ？at, ranging from 18.8 to 49.5 M , while also presenting a large span for those from C2H, ranging from 6.4 to 36.0 M . The line widths of both HNC and C2H look very similar, and both are wider than that of HC3N. The line widths of the three lines are all wider than those from dark clouds, implying that the former is more active than the latter, and has larger turbulence caused by winds and UV radiation from the surrounding massive stars.展开更多
基金supportedby the National Key R&D Program of China (No.2017YFA0402701)by the National Natural Science Foundation of China (Grant Nos. 11373026 and11433004)+2 种基金the Joint Research Fund in Astronomy(U1631237) under cooperative agreement between the National Natural Science Foundation of China and Chinese Academy of Sciencesby the Top TalentsProgram of Yunnan Province (2015HA030)by Yunnan University’s Research Innovation Fund for Graduate Students
文摘Previous observations have revealed an accretion disk and outflow motion in the high-mass starforming region G192.16–3.84, but collapse has not been reported before. Here we present molecular line and continuum observations toward the massive core G192.16–3.84 with the Submillimeter Array. C18 O(2–1) and HCO+(3–2) lines show pronounced blue profiles, indicating gas infalling in this region. This is the first time that infall motion has been reported in the G192.16–3.84 core. Two-layer model fitting gives infall velocities of 2.0±0.2 and 2.8±0.1 km s-1. Assuming that the cloud core follows a power-law density profile(ρ∝ r1.5), the corresponding mass infall rates are(4.7±1.7)×10-3 and(6.6±2.1)×10-3 M⊙yr-1 for C18 O(2–1) and HCO+(3–2), respectively. The derived infall rates are in agreement with the turbulent core model and those in other high-mass star-forming regions, suggesting that high accretion rate is a general requirement for forming a massive star.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11003046, 11073054, 10733030 and 10621303)the National Basic Research Program of China (973 Program, Grant 2007CB815403)
文摘For the first time, the OMC-2/3 region was mapped in C2H （1–0）, HC3N （10–9） and HNC （1–0） lines. In general, the emissions from all the three molecular species reveal an extended filamentary structure. The distribution of C2H cores almost follows that of the 1300μm condensations, which might suggest that C2H is a good tracer to study the core structure of molecular clouds. The core masses traced by HNC are rather ？at, ranging from 18.8 to 49.5 M , while also presenting a large span for those from C2H, ranging from 6.4 to 36.0 M . The line widths of both HNC and C2H look very similar, and both are wider than that of HC3N. The line widths of the three lines are all wider than those from dark clouds, implying that the former is more active than the latter, and has larger turbulence caused by winds and UV radiation from the surrounding massive stars.
