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  2. 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]

  3. Cometary knot - Wikipedia

    en.wikipedia.org/wiki/Cometary_knot

    On the near side of the Helix Nebula, the central dusty globule of each cometary knot appears dark against the background as it absorbs the [O III] 5007 Angstrom light emitted in the nebular envelope. Those on the far side do not obstruct this light source and so do not have this dark appearance. [6]

  4. File:NGC7293 (2004).jpg - Wikipedia

    en.wikipedia.org/wiki/File:NGC7293_(2004).jpg

    English: The Helix Nebula: a Gaseous Envelope Expelled By a Dying Star About the Object. Object Name: Helix Nebula, NGC 7293 or "The Eye of God" Object Description: Planetary Nebula; Position (J2000): R.A. 22h 29m 48.20s; Dec. -20° 49' 26.0" Constellation: Aquarius; Distance: About 690 light-years (213 parsecs)

  5. Sh 2-308 - Wikipedia

    en.wikipedia.org/wiki/Sh_2-308

    The nebula was formed about 70,000 years ago by the star EZ Canis Majoris throwing off its outer hydrogen layers, revealing inner layers of heavier elements. [2] Fast stellar winds, blowing at 1,700 km/s (3.8 million mph) from this star, create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of the star's evolution.

  6. List of largest nebulae - Wikipedia

    en.wikipedia.org/wiki/List_of_largest_nebulae

    Enormous Lyα nebula (ELAN) Four quasars embedded in the nebula. Likely progenitor of a massive galaxy cluster at z=2.05. Fabulous Nebula [13] 969,000 ly (297,000 pc) [14] Enormous Lyα nebula (ELAN) Also called SDSS J1020+1040 nebula, after the central quasar (aka 4C 10.29), located at z=3.164. Inspiraling material. [14]

  7. Nebular hypothesis - Wikipedia

    en.wikipedia.org/wiki/Nebular_hypothesis

    The visible-light (left) and infrared (right) views of the Trifid Nebula—a giant star-forming cloud of gas and dust located 5,400 light-years away in the constellation Sagittarius Stars are thought to form inside giant clouds of cold molecular hydrogen — giant molecular clouds roughly 300,000 times the mass of the Sun ( M ☉ ) and 20 ...

  8. Sculptor Galaxy - Wikipedia

    en.wikipedia.org/wiki/Sculptor_Galaxy

    Using the planetary nebula luminosity function method, an estimate of 10.89 +0.85 −1.24 million light years (or Mly; 3.34 +0.26 −0.38 Megaparsecs, or Mpc) was achieved in 2005. [2] The Sculptor Galaxy is close enough that the tip of the red-giant branch (TRGB) method may also be used to estimate its distance.

  9. Comet nucleus - Wikipedia

    en.wikipedia.org/wiki/Comet_nucleus

    The Helix Nebula has a cometary Oort cloud Comets, or their precursors, formed in the outer Solar System, possibly millions of years before planet formation. [ 38 ] How and when comets formed is debated, with distinct implications for Solar System formation, dynamics, and geology.