The ALMA-ATOMS study: Exploring Protostellar Outflows in HC3N

We present the first systematic study of bipolar outflows using HC3N as a tracer in a sample of 146 massive star-forming regions from ALMA-ATOMS survey. Protostellar outflows arise at the initial stage of star formation as a consequence of active accretion. Studies of these molecular outflows using different tracers provide important information about the physical and chemical phenomena in the protostellar outflows. In general, these outflows play a pivotal role in regulating the star formation processes by injecting energetic material in the parent molecular clouds. In such process, lower velocity components of outflows contain a significant portion of energetic. However, extraction of those component is difficult as the corresponding gas is often mixed with the cloud gas dynamics. In our sample, we identified 44 bipolar outflows and one explosive outflow in HC3N (J=11–10). The host cores of these outflows are found to be at different evolutionary stages, suggesting that outflows in HC3N are detectable in different stages of star formation. Analyses revealed that HC3N performs slightly better in detecting low velocity components of outflows than traditionally known tracers like SiO. The derived outflow parameters (i.e outflow mass, momentum, and energy) show moderate correlations with clump mass and luminosity. Overall, this study indicates that HC3N can be used as a complementary outflow tracer along with the traditionally known outflow tracers, particularly in the detection of the low-velocity components of outflows.