The precession of the HH 111 flow in the infrared

TL;DR

This paper uses infrared imaging to analyze the HH 111 outflow, revealing a mirror symmetric pattern likely caused by the orbital motion of a binary star system, modeled with an analytic ballistic approach.

Contribution

It provides the first evidence linking the outflow's symmetry to the orbital motion of a binary star system through detailed modeling.

Findings

Mirror symmetric pattern observed in jet and counterjet.

Binary system with two ~1 M_sun stars can produce the observed pattern.

Orbital motion around 186 AU separation explains the outflow structure.

Abstract

We present Spitzer IRAC images of the HH 111 outflow, that show a wealth of condensations/knots in both jet and counterjet. Studying the positional distribution of these knots, we find very suggestive evidence of a mirror symmetric pattern in the jet/counterjet flow. We model this pattern as the result of an orbital motion of the jet source around a binary companion. From a fit of an analytic, ballistic model to the observed path of the HH 111 system, we find that the motion in a binary with two approx. 1 Msolar stars (one of them being the HH 111 source), in a circular orbit with a separation of approx. 186 AU would produce the mirror symmetric pattern seen in the outflow.