Neutral Stellar Winds toward the High-mass Star-forming Region G176.51+00.20

Abstract

We observed the high-mass star-forming region G176.51+00.20 using the Five-hundred-meter Aperture Spherical radio Telescope with the 19 beam tracking observational mode. This is a pilot work of searching for neutral stellar winds traced by atomic hydrogen (i.e., H i winds) using the high-sensitivity H i line toward high-mass star-forming regions where bipolar molecular outflows have been detected with high sensitivity by Liu et al. H i wind was detected in this work only in Beam 1. We find here that, similar to low-mass star formation, no matter how large the inclination is, the H i wind is likely sufficiently strong to drive a molecular outflow. We also find that the abundance of H i in the H i wind is consistent with that of the H i narrow-line self-absorption (HINSA) in the same beam (i.e., Beam 1). This implies that there is probably an internal relationship between H i winds and HINSA. This result also reinforces the assertion that H i winds and detected molecular outflows are associated with each other.