A bipolar outflow from the massive protostellar core W51e2-E

TL;DR

This study uses high-resolution submillimeter observations to reveal a powerful bipolar outflow from the protostellar core W51e2-E, indicating active high-mass star formation distinct from the nearby HII region.

Contribution

It provides detailed imaging and analysis of the outflow from W51e2-E, demonstrating its origin, youth, and energetic properties, highlighting ongoing high-mass star formation.

Findings

Outflow originates from W51e2-E, not W51e2-W

Outflow age is about 1000 years, younger than the HII region

Mass loss rate is approximately 10^{-3} solar masses per year

Abstract

We present high resolution images of the bipolar outflow from W51e2, which are produced from the Submillimeter Array archival data observed for CO(3-2) and HCN(4-3) lines with angular resolutions of 0.8" x 0.6" and 0.3" x 0.2", respectively. The images show that the powerful outflow originates from the protostellar core W51e2-E rather than from the ultracompact HII region W51e2-W. The kinematic timescale of the outflow from W51e2-E is about 1000 yr, younger than the age (~5000 yr) of the ultracompact HII region W51e2-W. A large mass loss rate of ~1 x 10^{-3} M_sun yr^{-1} and a high mechanical power of 120 L_sun are inferred, suggesting that an O star or a cluster of B stars are forming in W51e2-E. The observed outflow activity along with the inferred large accretion rate indicates that at present W51e2-E is in a rapid phase of star formation.