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  2. List of planetary nebulae - Wikipedia

    en.wikipedia.org/wiki/List_of_planetary_nebulae

    Box Nebula NGC 6445: 1786 4.5 11.2 Sagittarius: Eye of Sauron Nebula M 1-42: 10 14 Sagittarius

  3. Nebula - Wikipedia

    en.wikipedia.org/wiki/Nebula

    Earth's air has a density of approximately 10 19 molecules per cubic centimeter; by contrast, the densest nebulae can have densities of 10 4 molecules per cubic centimeter. Many nebulae are visible due to fluorescence caused by embedded hot stars, while others are so diffused that they can be detected only with long exposures and special filters.

  4. 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. [42] (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 ...

  5. Lists of nebulae - Wikipedia

    en.wikipedia.org/wiki/Lists_of_nebulae

    The following articles contain lists of nebulae: List of dark nebulae; List of diffuse nebulae; List of largest nebulae; List of planetary nebulae;

  6. Lists of astronomical objects - Wikipedia

    en.wikipedia.org/wiki/Lists_of_astronomical_objects

    The Sun; Sirius A with Sirius B, a white dwarf; the Crab Nebula, a remnant supernova A black hole (artist concept); Vela Pulsar , a rotating neutron star M80 , a globular cluster , and the Pleiades , an open star cluster

  7. List of largest nebulae - Wikipedia

    en.wikipedia.org/wiki/List_of_largest_nebulae

    The following well-known nebulae are listed for the purpose of comparison. Orion Nebula: 20 ly (6.132 pc) [64] Diffuse Nebula: The closest major star formation region to Earth. [65] Crab Nebula: 11 ly (3.4 pc) [66] Supernova remnant: The remnant of a supernova that occurred in 1054 AD. [67] Bubble Nebula: 6 [68]-10 [69] [70] ly (1.84-3.066 pc ...

  8. Galaxy - Wikipedia

    en.wikipedia.org/wiki/Galaxy

    Subsequently, William Herschel assembled a catalog of 5,000 nebulae. [34] In 1845, Lord Rosse examined the nebulae catalogued by Herschel and observed the spiral structure of Messier object M51, now known as the Whirlpool Galaxy. [44] [45] In 1912, Vesto M. Slipher made spectrographic studies of the brightest spiral nebulae to determine their ...

  9. Horsehead Nebula - Wikipedia

    en.wikipedia.org/wiki/Horsehead_Nebula

    The Horsehead Nebula (also known as Barnard 33 or B33) is a small dark nebula in the constellation Orion. [2] The nebula is located just to the south of Alnitak , the easternmost star of Orion's Belt , and is part of the much larger Orion molecular cloud complex .