![Composite picture of the Cat’s Eye Nebula (NGC 6543), combining three images taken by the Hubble …[Credits : Photo AURA/STScI/NASA/JPL (NASA photo # STScI-PRC95-01a)]](http://media-2.web.britannica.com/eb-media/36/21236-003-CC938BFC.gif)
any of a class of bright nebulae that are expanding shells of luminous gas expelled by dying stars. Observed telescopically, they have a relatively round, compact appearance rather than the chaotic, patchy shapes of other nebulae—hence their name, which was given because of their resemblance to planetary disks when viewed with the instruments of the late 1700s, when the first planetary nebulae were discovered.
Composite-picture-of-the-Cats-Eye-Nebula-combining-three-imagesComposite picture of the Cat’s Eye Nebula (NGC 6543), combining three images taken by the Hubble …[Credits : Photo AURA/STScI/NASA/JPL (NASA photo # STScI-PRC95-01a)]
Two-computer-coloured-images-of-the-Cats-Eye-Nebula-madeTwo computer-coloured images of the Cat’s Eye Nebula (NGC 6543) made from data gathered by …[Credits : NASA; (left) UIUC/Y.Chu et al.; (right) HST]
Planetary-Nebula-Hen-1357-as-photographed-by-the-Hubble-SpacePlanetary Nebula Hen 1357, as photographed by the Hubble Space Telescope.[Credits : National Aeronautics and Space Administration]
Image-of-MyCn18-a-young-planetary-nebula-located-about-8000Image of MyCn18, a young planetary nebula located about 8,000 light-years away, taken with the Wide …[Credits : Photo AURA/STScl/NASA/JPL (NASA photo # STScl-PRC96-07)]
Ring-Nebula-in-the-constellation-Lyra-a-planetary-nebula-consistingRing Nebula (M57, NGC 6720) in the constellation Lyra, a planetary nebula consisting mainly of …[Credits : Hale Observatories ©1959]
Link to this article and share the full text with the readers of your Web site or blog-post.
If you think a reference to this article on "planetary nebula" will enhance your Web site,
blog-post, or any other web-content, then feel free to link to this article,
and your readers will gain full access to the full article, even if they do not subscribe to our service.
You may want to use the HTML code fragment provided below.
We welcome your comments. Any revisions or updates suggested for this article will be reviewed by our editorial staff. Contact us here.
Regular users of Britannica may notice that this comments feature is less robust than in the past. This is only temporary, while we make the transition to a dramatically new and richer site. The functionality of the system will be restored soon.