High resolution imaging of NGC 2346 with GSAOI/GeMS: disentangling the planetary nebula molecular structure to understand its origin and evolution

TL;DR

This study uses high-resolution imaging to reveal detailed molecular hydrogen structures in NGC 2346, showing knots and filaments that suggest a specific formation mechanism driven by nebular gas dynamics.

Contribution

First high-resolution images of H$_2$ gas in NGC 2346 reveal detailed structures, providing new insights into nebular formation and evolution mechanisms.

Findings

H$_2$ gas consists of knots and filaments, not a uniform torus.

Clump formation is linked to nebular gas pressure dynamics.

High spatial resolution enables detailed structural analysis.

Abstract

We present high spatial resolution ($\approx$ 60--90 milliarcseconds) images of the molecular hydrogen emission in the Planetary Nebula (PN) NGC 2346. The data were acquired during the System Verification of the Gemini Multi-Conjugate Adaptive Optics System + Gemini South Adaptive Optics Imager. At the distance of NGC 2346, 700 pc, the physical resolution corresponds to $\approx$ 56 AU, which is slightly higher than that an [N II] image of NGC 2346 obtained with HST/WFPC2. With this unprecedented resolution we were able to study in detail the structure of the H$_2$ gas within the nebula for the first time. We found it to be composed of knots and filaments, which at lower resolution had appeared to be a uniform torus of material. We explain how the formation of the clumps and filaments in this PN is consistent with a mechanism in which a central hot bubble of nebular gas surrounding the central star has been depressurized, and the thermal pressure of the photoionized region drives the fragmentation of the swept-up shell.