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  2. 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. The term originates from the planet-like round shape of these nebulae observed by astronomers through ...

  3. List of planetary nebulae - Wikipedia

    en.wikipedia.org/wiki/List_of_planetary_nebulae

    Cat's Eye Nebula: NGC 6543: 1786 3.3 ± 0.9 9.8B Draco: Little Ghost Nebula: NGC 6369: 1800 (prior to) 2 ± 3 9.9 Ophiuchus: Medusa Nebula: Abell 21 1955 1.0 (approx.) 15.99 Gemini: Jewel Bug Nebula: NGC 7027: 1878 3.0 (approx.) 10 Cygnus: Helix Nebula: NGC 7293: 1824 0.68 +0.15 −0.08: 7.6 Aquarius: Little Dumbbell Nebula: M76: NGC 650, NGC ...

  4. Nebula - Wikipedia

    en.wikipedia.org/wiki/Nebula

    The Westbrook Nebula, a protoplanetary 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) [a] phase and the subsequent planetary nebula (PN) phase.

  5. Nebular hypothesis - Wikipedia

    en.wikipedia.org/wiki/Nebular_hypothesis

    However, the minimum mass nebula capable of terrestrial planet formation can only form 1–2 M E cores at the distance of Jupiter (5 AU) within 10 million years. [65] The latter number represents the average lifetime of gaseous disks around Sun-like stars. [ 17 ]

  6. List of largest nebulae - Wikipedia

    en.wikipedia.org/wiki/List_of_largest_nebulae

    NGC 604, one of largest nebulae (H II region) is located in the Triangulum Galaxy (viewed by the Hubble Space Telescope).. Below is a list of the largest known nebulae so far discovered, ordered by actual diameter.

  7. 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 ]

  8. Lists of astronomical objects - Wikipedia

    en.wikipedia.org/wiki/Lists_of_astronomical_objects

    Comet Lovejoy and Jupiter, a giant gas planet; 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; The Whirlpool galaxy and Abell 2744, a galaxy cluster; Superclusters, galactic ...

  9. Cat's Eye Nebula - Wikipedia

    en.wikipedia.org/wiki/Cat's_Eye_Nebula

    At the centre of the Cat's Eye Nebula is a dying Wolf Rayet star, the sort of which can be seen in the Webb Telescope's image of WR 124. The Cat's Eye Nebula's central star shines at magnitude +11.4. Hubble Space Telescope images show a sort of dart board pattern of concentric rings emanating outwards from the centre.