Protostellar outflows in HC3N, an unusual outflow tracer

ABSTRACT :
Protostellar outflows are ubiquitous in both low and high mass star formation. Outflows are considered as a signpost of active star formation. On passing through molecular clouds, outflows cause shock within molecular gas which can be traced using tracers which are sensitive to shock. The interstellar HC$_3$N (Cyanoacetylene) molecular line is typically known to trace dense regions of molecular clouds, since they tend to be destroyed by ultraviolet radiation in low density environments. Both chemical modeling and observational studies of HC$_3$N suggest the enhancement of HC$_3$N abundance in shocked region. However, high velocity outflow wings are also found in the spectral profile of HC$_3$N in previous studies. In this study, we identified protostellar outflows in a sample of 146 active star forming regions of the ATOMS (ALMA Three-millimeter Observations of Massive Star-forming regions) survey using HC$_3$N (J=11-10) tracer, and outflows are identified in about 42 regions. We have identified 46 bipolar outflows and one explosive outflow. We estimated several outflow parameters (such as, outflow terminal velocity, mass, momentum, energy) and investigated their correlation with clump properties and the evolutionary state of the outflow driving cores. We found a moderate correlation between outflow mass and clump luminosity (Pearson correlation coefficient=0.6). However, we also noted a weak correlation between outflow energy and clump luminosity (Pearson correlation coefficient=0.4). Details of the identification methods and results will be presented.