Spitzer imaging of the jet driving the NGC 2264 G outflow

TL;DR

This study uses Spitzer IRAC imaging to map the NGC 2264 G protostellar outflow, revealing a continuous jet structure, its association with the driving source VLA 2, and evidence of jet precession affecting outflow morphology.

Contribution

First infrared imaging showing the full extent of the jet and its connection to the driving source, with analysis of jet precession as a key factor in outflow morphology.

Findings

Jet extends over entire red outflow lobe

Jet likely precesses with an ~8000-year period

Jet morphology explains outflow broadening

Abstract

We present new infrared imaging of the NGC 2264 G protostellar outflow region, obtained with the InfraRed Array Camera (IRAC) on-board the Spitzer Space Telescope. A jet in the red outflow lobe (eastern lobe) is clearly detected in all four IRAC bands and, for the first time, is shown to continuously extend over the entire length of the red outflow lobe traced by CO observations. The redshifted jet also extends to a deeply embedded Class 0 source, VLA 2, confirming previous suggestions that it is the driving source of the outflow (Gomez et al. 1994). The images show that the easternmost part of the redshifted jet exhibits what appear to be multiple changes of direction. To understand the redshifted jet morphology we explore several mechanisms that could generate such apparent changes of direction. From this analysis, we conclude that the redshifted jet structure and morphology visible in the IRAC images can be largely, although not entirely, explained by a slowly precessing jet (period ~8000 yr) that lies mostly on the plane of the sky. It appears that the observed changes in the redshifted jet direction may be sufficient to account for a significant fraction of the broadening of the outflow lobe observed in the CO emission.