Neutral Stellar Winds Toward the High-Mass Star-Forming Region G176.51+00.20

TL;DR

This study used FAST to detect atomic hydrogen winds in a high-mass star-forming region, suggesting a link between HI winds and molecular outflows, and providing insights into stellar wind mechanisms.

Contribution

First detection of HI stellar winds in a high-mass star-forming region using FAST, indicating a potential internal relationship with HINSA and molecular outflows.

Findings

HI wind detected in one beam with high sensitivity

HI wind likely drives molecular outflows regardless of inclination

HI abundance in wind matches that of HINSA

Abstract

We observed the high-mass star-forming region G176.51+00.20 using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) with the 19-beam tracking observational mode. This is a pilot work of searching for neutral stellar winds traced by atomic hydrogen (i.e., HI winds) using the high sensitivity HI line toward high-mass star-forming regions where bipolar molecular outflows have been detected with high sensitivity by Liu et al. HI 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 HI wind is likely sufficiently strong to drive a molecular outflow. We also find that the abundance of HI in the HI wind is consistent with that of the HI narrow-line self-absorption (HINSA) in the same beam (i.e., Beam 1). This implies that there is probably an internal relationship between HI winds and HINSA. This result also reinforces the assertion that HI winds and detected molecular outflows are associated with each other.