Fast, low-ionization emission regions of the planetary nebula M2-42

TL;DR

This study uses spatially resolved spectroscopy to analyze the bipolar jets of planetary nebula M2-42, revealing their velocities, densities, and ionization states, and modeling their three-dimensional structure.

Contribution

It provides the first detailed 3D morpho-kinematic model of M2-42's jets and characterizes their physical and chemical properties, highlighting their classification as fast, low-ionization emission regions.

Findings

Jets have deprojected velocities of 80-160 km/s.

Jets' density is five times lower than the main shell.

Jets' nitrogen and sulfur abundances are about three times higher.

Abstract

Spatially resolved observations of the planetary nebula M2-42 (PN G008.2-04.8) obtained with the Wide Field Spectrograph on the Australian National University 2.3 m telescope have revealed the remarkable features of bipolar collimated jets emerging from its main structure. Velocity-resolved channel maps derived from the [N II] $\lambda$6584 emission line disentangle different morphological components of the nebula. This information is used to develop a three-dimensional morpho-kinematic model, which consists of an equatorial dense torus and a pair of asymmetric bipolar outflows. The expansion velocity of about 20 km s$^{-1}$ is measured from the spectrum integrated over the main shell. However, the deprojected velocities of the jets are found to be in the range of 80-160 km s$^{-1}$ with respect to the nebular center. It is found that the mean density of the collimated outflows, 595 $\pm$ 125 cm$^{-3}$, is five times lower than that of the main shell, 3150 cm$^{-3}$, whereas their singly ionized nitrogen and sulfur abundances are about three times higher than those determined from the dense shell. The results indicate that the features of the collimated jets are typical of fast, low-ionization emission regions.