Outflow 202000 AU from a High-Mass Protostar in W51-IRS 2

摘要

We present the results of the first high angular resolution observations of SiO maser emission toward the star-forming region W51-IRS 2 made with the Very Large Array (VLA) and Very Long Baseline Array (VLBA). Our images of the H_2O maser emission in W51-IRS 2 reveal two maser complexes bracketing the SiO maser source. One of these H_2O maser complexes appears to trace a bow shock whose opening angle is consistent with the opening angle observed in the distribution of SiO maser emission. A comparison of our H_2O maser image with an image constructed from data acquired 19 years earlier clearly shows the persistence and motion of this bow shock.