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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 ...
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.
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 ...
The Ring Nebula is located in the lower right of the image Gum Nebula: 809–950 ly (248–291 pc) [16] [17] Emission nebula: Extends about 36° of the sky Bubble Nebula (NGC 6822) 758 ly (232 pc) [18] [19] [20] H II region: The Bubble Nebula is located in the upper left of the image NGC 6188: 600 ly (180 pc) [21] Emission nebula: NGC 592
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 ]
It was originally named the Andromeda Nebula and is cataloged as Messier 31, M31, and NGC 224. Andromeda has a D 25 isophotal diameter of about 46.56 kiloparsecs (152,000 light-years ) [ 8 ] and is approximately 765 kpc (2.5 million light-years) from Earth.
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 Dumbbell Nebula (also known as the Apple Core Nebula, Messier 27, and NGC 6853) is a planetary nebula (nebulosity surrounding a white dwarf) in the constellation Vulpecula, at a distance of about 1360 light-years. [1] It was the first such nebula to be discovered, by Charles Messier in 1764.