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  2. Emission nebula - Wikipedia

    en.wikipedia.org/wiki/Emission_nebula

    Planetary nebulae, represented here by the Ring Nebula, are examples of emission nebulae. An emission nebula is a nebula formed of ionized gases that emit light of various wavelengths. The most common source of ionization is high-energy ultraviolet photons emitted from a nearby hot star .

  3. Nebula - Wikipedia

    en.wikipedia.org/wiki/Nebula

    Diffuse nebulae can be divided into emission nebulae, reflection nebulae and dark nebulae. Visible light nebulae may be divided into emission nebulae, which emit spectral line radiation from excited or ionized gas (mostly ionized hydrogen ); [ 25 ] they are often called H II regions , H II referring to ionized hydrogen), and reflection nebulae ...

  4. N44 (emission nebula) - Wikipedia

    en.wikipedia.org/wiki/N44_(emission_nebula)

    N44 is an emission nebula with superbubble structure located in the Large Magellanic Cloud, a satellite galaxy of the Milky Way in the constellation Dorado. [ 3 ] [ 4 ] [ 5 ] Originally catalogued in Karl Henize 's "Catalogue of H-alpha emission stars and nebulae in the Magellanic Clouds" of 1956, it is approximately 1,000 light-years wide and ...

  5. Photoluminescence - Wikipedia

    en.wikipedia.org/wiki/Photoluminescence

    Photoluminescence (abbreviated as PL) is light emission from any form of matter after the absorption of photons (electromagnetic radiation). [1] It is one of many forms of luminescence (light emission) and is initiated by photoexcitation (i.e. photons that excite electrons to a higher energy level in an atom), hence the prefix photo- . [ 2 ]

  6. Nebulium - Wikipedia

    en.wikipedia.org/wiki/Nebulium

    Cat's Eye Nebula (NGC 6543) Cat's Eye Nebula (NGC 6543) Nebulium was a proposed element found in astronomical observation of a nebula by William Huggins in 1864. The strong green emission lines of the Cat's Eye Nebula, discovered using spectroscopy, led to the postulation that an as yet unknown element was responsible for this emission.

  7. Planetary nebula - Wikipedia

    en.wikipedia.org/wiki/Planetary_nebula

    A planetary nebula is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. [ 4 ] The term "planetary nebula" is a misnomer because they are unrelated to planets .

  8. NGC 1491 - Wikipedia

    en.wikipedia.org/wiki/NGC_1491

    NGC 1491, also known as LBN 704, SH2-206 or the Fossil Footprint Nebula, is an emission type bright nebula located about 9,800 light years away from Earth in the constellation of Perseus. [1] The nebula gets its deep red coloration due to many massive stars (such as BD+50 866 ) embedded within NGC 1491 producing large amounts of ultraviolet ...

  9. Lyman-alpha blob - Wikipedia

    en.wikipedia.org/wiki/Lyman-alpha_blob

    Animation of a Lyman-alpha blob. The giant Lyman-alpha blob LAB-1 (left) and an artist's impression of what it might look like if viewed from relatively close (right).. In astronomy, a Lyman-alpha blob (LAB) is a huge concentration of a gas emitting the Lyman-alpha emission line.