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  2. Nebula - Wikipedia

    en.wikipedia.org/wiki/Nebula

    A nebula that is visible to the human eye from Earth would appear larger, but no brighter, from close by. [6] The Orion Nebula, the brightest nebula in the sky and occupying an area twice the angular diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers. [7]

  3. Nebular hypothesis - Wikipedia

    en.wikipedia.org/wiki/Nebular_hypothesis

    The heating of the disk is primarily caused by the viscous dissipation of turbulence in it and by the infall of the gas from the nebula. [39] [40] The high temperature in the inner disk causes most of the volatile material—water, organics, and some rocks—to evaporate, leaving only the most refractory elements like iron. The ice can survive ...

  4. NGC 7027 - Wikipedia

    en.wikipedia.org/wiki/NGC_7027

    The nebula is rich in carbon, and is a very interesting object for the study of carbon chemistry in dense molecular material exposed to strong ultraviolet radiation. [18] The spectrum of NGC 7027 contains fewer spectral lines from neutral molecules than is usual for planetary nebulae.

  5. NGC 281 - Wikipedia

    en.wikipedia.org/wiki/NGC_281

    IC 11, Sh2-184, [3] Sharpless 184, [1] LBN 616, LBN 123.17-06.28, Pacman Nebula See also: Lists of nebulae NGC 281 , IC 11 or Sh2-184 is a bright emission nebula and part of an H II region in the northern constellation of Cassiopeia and is part of the Milky Way 's Perseus Spiral Arm .

  6. Bok globule - Wikipedia

    en.wikipedia.org/wiki/Bok_globule

    In astronomy, Bok globules are isolated and relatively small dark nebulae containing dense cosmic dust and gas from which star formation may take place. Bok globules are found within H II regions, and typically have a mass of about two [1] to 50 solar masses contained within a region about a light year or so across (about 4.5 × 10 47 m 3). [2]

  7. Emission nebula - Wikipedia

    en.wikipedia.org/wiki/Emission_nebula

    The nebula's color depends on its chemical composition and degree of ionization. Due to the prevalence of hydrogen in interstellar gas, and its relatively low energy of ionization, many emission nebulae appear red due to strong emissions of the Balmer series. If more energy is available, other elements will be ionized, and green and blue ...

  8. Owl Nebula - Wikipedia

    en.wikipedia.org/wiki/Owl_Nebula

    The Owl Nebula (also known as Messier 97, M97 or NGC 3587) is a planetary nebula approximately 2,030 light years away in the constellation Ursa Major. [2] Estimated to be about 8,000 years old, [ 6 ] it is approximately circular in cross-section with a faint internal structure.

  9. Reflection nebula - Wikipedia

    en.wikipedia.org/wiki/Reflection_nebula

    The energy from the nearby stars is insufficient to ionize the gas of the nebula to create an emission nebula, but is enough to give sufficient scattering to make the dust visible. Thus, the frequency spectrum shown by reflection nebulae is similar to that of the illuminating stars. Among the microscopic particles responsible for the scattering ...