An Ordered Bipolar Outflow from a Massive Early-Stage Core

TL;DR

This study presents ALMA observations of two massive early-stage cores in an IRDC, revealing a highly collimated bipolar outflow from one core, indicating early massive star formation with ordered accretion processes similar to low-mass protostars.

Contribution

It provides the first detailed ALMA imaging of an ordered bipolar outflow from a massive early-stage core, supporting models of early massive star formation.

Findings

Detection of a highly-collimated bipolar outflow from C1-Sa

C1-Sa is a promising early-stage massive protostar

Evidence of ordered accretion processes in early massive star formation

Abstract

We present ALMA follow-up observations of two massive, early-stage core candidates, C1-N & C1-S, in Infrared Dark Cloud (IRDC) G028.37+00.07, which were previously identified by their N2D+(3-2) emission and show high levels of deuteration of this species. The cores are also dark at far infrared wavelengths up to ~100 microns. We detect 12CO(2-1) from a narrow, highly-collimated bipolar outflow that is being launched from near the center of the C1-S core, which is also the location of the peak 1.3mm dust continuum emission. This protostar, C1-Sa, has associated dense gas traced by C18O(2-1) and DCN(3-2), from which we estimate it has a radial velocity that is near the center of the range exhibited by the C1-S massive core. A second outflow-driving source is also detected within the projected boundary of C1-S, but appears to be at a different radial velocity. After considering properties of the outflows, we conclude C1-Sa is a promising candidate for an early-stage massive protostar and as such it shows that these early phases of massive star formation can involve highly ordered outflow, and thus accretion, processes, similar to models developed to explain low-mass protostars.