Abstract Previous observations have revealed an accretion disk and outflow motion in the high-mass star-forming 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. C18O(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)×10−3M⊙ yr−1 for C18O(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.
Keywords ISM: individual objects (G192.16–3.84) — ISM: molecules — stars: formation
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