Ionization driven molecular outflow in K3-50A

TL;DR

This study presents the first observation of an ionized outflow entraining molecular gas in K3-50A, providing evidence that high mass stars may continue accreting material even after ionization begins.

Contribution

It offers new observational evidence of ionized outflow entraining molecular gas, supporting models of ongoing accretion in high mass star formation.

Findings

Ionized outflow is entraining molecular gas in K3-50A.

Evidence suggests ongoing accretion in the presence of ionization.

First observation of such an outflow driven by photoionized gas.

Abstract

Whether high mass stars continue to accrete material beyond the formation of an HII region is still an open question. Ionized infall and outflow have been seen in some sources, but their ties to the surrounding molecular gas are not well constrained. We aim to quantify the ionized and molecular gas dynamics in a high mass star forming region (K3-50A) and their interaction. We present CARMA observations of the 3mm continuum, H41\alpha, and HCO+ emission, and VLA continuum observations at 23 GHz and 14.7 GHz to quantify the gas and its dynamics in K3-50A. We find large scale dynamics consistent with previous observations. On small scales, we find evidence for interaction between the ionized and molecular gas which suggests the ionized outflow is entraining the molecular one. This is the first time such an outflow entrained by photo ionized gas has been observed. Accretion may be ongoing in K3-50A because an ionized bipolar outflow is still being powered, which is in turn entraining part of the surrounding molecular gas. This outflow scenario is similar to that predicted by ionization feedback models.