Discovery of Multiple Shells Around the Planetary Nebula IC 418

TL;DR

This study uses optical, near-, and mid-infrared imaging to reveal multiple faint shells and structures around the planetary nebula IC 418, providing new insights into its morphology and evolution.

Contribution

First detailed multi-wavelength imaging analysis uncovering multiple shells and faint structures around IC 418, highlighting the importance of IR imaging for studying planetary nebulae.

Findings

Detection of three concentric rings and two detached haloes.

Estimated ages of haloes range from 10,000 to 50,000 years.

Near- and mid-IR imaging effectively reveal faint nebular structures.

Abstract

We have analysed optical, near-, and mid-IR images of the bright planetary nebula (PN) IC 418. These images probe unambiguously for the first time a number of low surface brightness structures and shells around the bright main nebula, including radial filaments or rays, a system of three concentric rings, and two detached haloes with sizes ~ 150" and 220"\times250", respectively. The main nebula is slightly off-centered with respect to the elliptical outer halo. The time-lapse between the two haloes is 10,000-50,000 yr, whereas the time-lapse between the three concentric rings is ~ 630 yr. We emphasize the advantages of near- and mid-IR imaging for the detection of faint structures and shells around optically bright nebulae.