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  2. Planetary nebula - Wikipedia

    en.wikipedia.org/wiki/Planetary_nebula

    A typical planetary nebula is roughly one light year across, and consists of extremely rarefied gas, with a density generally from 100 to 10,000 particles per cm 3. [40] (The Earth's atmosphere, by comparison, contains 2.5 × 10 19 particles per cm 3.) Young planetary nebulae have the highest densities, sometimes as high as 10 6 particles per ...

  3. List of largest nebulae - Wikipedia

    en.wikipedia.org/wiki/List_of_largest_nebulae

    List of the largest nebulae Image Nebula Maximum dimension (in light-years/parsecs) Type Notes NGC 262 Halo Cloud 1,300,000 ly (400,000 pc) [1] H I region: Spiral nebula surrounding NGC 262, which is one of the largest known galaxies. Leo Ring: 650,000 ly (200,000 pc) [2] HVC: A large ring of cold gas that formed from a collision of two ...

  4. List of planetary nebulae - Wikipedia

    en.wikipedia.org/wiki/List_of_planetary_nebulae

    Cat's Eye Nebula: NGC 6543: 1786 3.3 ± 0.9 9.8B Draco: Little Ghost Nebula: NGC 6369: 1800 (prior to) 2 ± 3 9.9 Ophiuchus: Medusa Nebula: Abell 21 1955 1.0 (approx.) 15.99 Gemini: Jewel Bug Nebula: NGC 7027: 1878 3.0 (approx.) 10 Cygnus: Helix Nebula: NGC 7293: 1824 0.68 +0.15 −0.08: 7.6 Aquarius: Little Dumbbell Nebula: M76: NGC 650, NGC ...

  5. NGC 7027 - Wikipedia

    en.wikipedia.org/wiki/NGC_7027

    NGC 7027 is unusually small, measuring only 0.2 by 0.1 light-years, whereas the typical size for a planetary nebula is 1 light-year. [4] It is fairly young, at about 600 years old. [12] It has a very complex shape, consisting of an elliptical region of ionized gas [13] and an equatorial belt [14] within a massive neutral cloud. [15]

  6. NGC 6445 - Wikipedia

    en.wikipedia.org/wiki/NGC_6445

    NGC 6445, also known as the Little Gem Nebula or Box Nebula, is a planetary nebula in the constellation Sagittarius. It was discovered by William Herschel on May 28, 1786. [ 6 ] The distance of NGC 6445 is estimated to be slightly more than 1,000 parsecs based on the parallax measured by Gaia , which was measured at 0.9740 ± 0.3151 mas.

  7. NGC 2792 - Wikipedia

    en.wikipedia.org/wiki/NGC_2792

    NGC 2792 is a planetary nebula located in the constellation Vela. [1] NGC 2792 was discovered by British astronomer John ... The apparent size of the nebula is 0.350 ...

  8. Nebula - Wikipedia

    en.wikipedia.org/wiki/Nebula

    The Oyster Nebula is a planetary nebula located in the constellation of Camelopardalis. Planetary nebulae are the remnants of the final stages of stellar evolution for mid-mass stars (varying in size between 0.5-~8 solar masses).

  9. NGC 7662 - Wikipedia

    en.wikipedia.org/wiki/NGC_7662

    It is known as the Blue Snowball Nebula, Snowball Nebula, and Caldwell 22. This nebula was discovered October 6, 1784 by the German-born English astronomer William Herschel . In the New General Catalogue it is described as a "magnificent planetary or annular nebula, very bright, pretty small in angular size , round, blue, variable nucleus".