The H2 Amazing Life of NGC 6881

TL;DR

This study analyzes optical and near-IR images and spectra of NGC 6881, revealing its multiple bipolar lobes formed at different evolutionary phases with shock-excited H2 emission, indicating changing collimation conditions.

Contribution

It provides new multi-wavelength observations and analysis confirming the complex bipolar structure and shock excitation in NGC 6881, highlighting evolving collimation mechanisms.

Findings

H2 is predominantly shock excited in NGC 6881

NGC 6881 has multiple bipolar lobes from different phases

Collimation conditions changed between ejection events

Abstract

The H2 and optical (Ha, [NII]) morphology of NGC 6881 are very different. Here we present a preliminary report of the analysis of new optical (Ha and [NII]) and near-IR (Brg and H2) images and intermediate resolution JHK spectra of this nebula. Our observations confirm the association of the H2 bipolar lobes to NGC 6881 and reveal that H2 is predominantly shock excited in this nebula. We conclude that NGC 6881 has multiple bipolar lobes that formed at different phases of the nebular evolution and that the collimation conditions or even the collimating agent changed from one ejection to the other.