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  2. Nebula - Wikipedia

    en.wikipedia.org/wiki/Nebula

    A protoplanetary nebula or preplanetary nebula [27] (PPN, plural PPNe) is an astronomical object which is at the short-lived episode during a star's rapid evolution between the late asymptotic giant branch (LAGB) phase and the subsequent planetary nebula (PN) phase.

  3. Emission nebula - Wikipedia

    en.wikipedia.org/wiki/Emission_nebula

    An emission nebula is a nebula formed of ionized gases that emit light of various ... Many nebulae are made up of both reflection and emission components such as the ...

  4. 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 .

  5. Planetary nebula - Wikipedia

    en.wikipedia.org/wiki/Planetary_nebula

    The first planetary nebula discovered (though not yet termed as such) was the Dumbbell Nebula in the constellation of Vulpecula.It was observed by Charles Messier on July 12, 1764 and listed as M27 in his catalogue of nebulous objects. [10]

  6. Dark nebula - Wikipedia

    en.wikipedia.org/wiki/Dark_nebula

    A dark nebula or absorption nebula is a type of interstellar cloud, particularly molecular clouds, that is so dense that it obscures the visible wavelengths of light from objects behind it, such as background stars and emission or reflection nebulae.

  7. Orion Nebula - Wikipedia

    en.wikipedia.org/wiki/Orion_nebula

    The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion, and is known as the middle "star" in the "sword" of Orion.

  8. Reflection nebula - Wikipedia

    en.wikipedia.org/wiki/Reflection_nebula

    Reflection nebula are usually blue because the scattering is more efficient for blue light than red (this is the same scattering process that gives us blue skies and red sunsets). Reflection nebulae and emission nebulae are often seen together and are sometimes both referred to as diffuse nebulae. Some 500 reflection nebulae are known.

  9. Helix Nebula - Wikipedia

    en.wikipedia.org/wiki/Helix_nebula

    The Helix Nebula (also known as NGC 7293 or Caldwell 63) is a planetary nebula (PN) located in the constellation Aquarius. Discovered by Karl Ludwig Harding, most likely before 1824, this object is one of the closest of all the bright planetary nebulae to Earth. [3] The distance, measured by the Gaia mission, is 655±13 light-years. [4]