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Keywords:

  • ISM: jets and outflows;
  • ISM: lines and bands;
  • planetary nebulae: individual: IC 418;
  • infrared: ISM

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 arcsec and inline image, respectively. The main nebula is slightly off-centred 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.