Halo of the Cat’s Eye
The Cat's Eye Nebula
(NGC 6543) is one of the best known planetary
nebulae in the sky.
Its haunting symmetries are seen
in the very central region of
this stunning false-color picture, processed to reveal the
enormous but extremely faint halo of gaseous material, over three
light-years across, which surrounds the brighter,
familiar
planetary nebula.
Made with data from the
Nordic Optical Telescope in the
Canary Islands,
the composite picture shows extended emission from the nebula.
Planetary
nebulae have long been appreciated as a final phase
in the life of a sun-like star.
Only much more recently however, have some planetaries been
found to have halos
like this one, likely formed of material shrugged off during
earlier active episodes in the star's evolution.
While the planetary
nebula phase is thought to last for around 10,000 years,
astronomers estimate the age of the
outer filamentary portions
of this halo to be 50,000 to 90,000 years.
