High Angular Resolution Observations at 7-mm of the Core of the Quadrupolar HH 111/121 Outflow

TL;DR

This study uses high-resolution 7-mm VLA observations to analyze the core of the quadrupolar HH 111/121 outflow, revealing a complex structure likely involving circumstellar disks or a disk-jet system.

Contribution

First high-resolution 7-mm observations of the HH 111/121 outflow core, providing insights into its structure and possible disk or jet configurations.

Findings

Detected two overlapping elongated sources perpendicular to each other.

Estimated dust dominates the 7-mm continuum emission with some free-free contribution.

Identified structures suggest either circumstellar disks or a disk-jet system.

Abstract

We present sensitive, high angular resolution ($0\rlap.{''}05$) VLA continuum observations made at 7 mm of the core of the HH 111/121 quadrupolar outflow. We estimate that at this wavelength the continuum emission is dominated by dust, although a significant free-free contribution ($\sim$30%) is still present. The observed structure is formed by two overlapping, elongated sources approximately perpendicular to each other as viewed from Earth. We interpret this structure as either tracing two circumstellar disks that exist around each of the protostars of the close binary source at the core of this quadrupolar outflow or a disk and a jet perpendicular to it. Both interpretations have advantages and disadvantages, and future high angular resolution spectroscopic millimeter observations are required to favor one of them in a more conclusive way.