2010, ISBN: 9781155252070

[ED: Pappeinband], [PU: Bertrams Print On Demand], - Source: Wikipedia. Pages: 30. Chapters: Planetary nebula, Ring Nebula, Cat's Eye Nebula, NGC 6302, Helix Nebula, NGC 7027, Mz 3, Dumbb… Meer...

[ED: Pappeinband], [PU: Bertrams Print On Demand], - Source: Wikipedia. Pages: 30. Chapters: Planetary nebula, Ring Nebula, Cat's Eye Nebula, NGC 6302, Helix Nebula, NGC 7027, Mz 3, Dumbbell Nebula, Planetary Nebula M2-9, List of planetary nebulae, Planetary nebula luminosity function, Abell 39, Little Dumbbell Nebula, Saturn Nebula, Stingray Nebula, Eskimo Nebula, NGC 2818, NGC 1514, Hourglass Nebula, Mz 1, Medusa Nebula, NGC 2440, Zanstra method, NGC 6826, NGC 7662, NGC 3242, NGC 3132, Owl Nebula, IC 4406, NGC 6751, Fast Low-Ionization Emission Region, NGC 2371-2, NGC 40, Red Spider Nebula, NGC 6072, IC 418, Soap bubble nebula, NGC 6741, NGC 2438, NGC 3195, NGC 6572, Little Ghost Nebula, NGC 3918, NGC 2867, NGC 246, Shapley 1, NGC 7008, NGC 2346, NGC 6818, Hen 2-47, NGC 5189, NGC 6210, NGC 2022, NGC 6578, NGC 6884, NGC 6790, NGC 5307, NGC 5315, NGC 6565, NGC 7354, Lemon slice nebula, NGC 5882, NGC 6781, M1-92, NGC 2899, NGC 1360, IC 289, NGC 7048, NGC 1535, IC 2448, IC 2149. Excerpt: A planetary nebula is an emission nebula consisting of an expanding glowing shell of ionized gas ejected during the asymptotic giant branch phase of certain types of stars late in their life. This name originated with their first discovery in the 18th century because of their similarity in appearance to giant planets when viewed through small optical telescopes, and is otherwise unrelated to the planets of the solar system. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years. At the end of the star's life, during the red giant phase, the outer layers of the star are expelled via pulsations and strong stellar winds. Without these opaque layers, the hot, luminous core emits ultraviolet radiation that ionizes the ejected outer layers of the star. This energized shell radiates as a planetary nebula. Planetary nebulae play a crucial role in the chemical evolution of the galaxy, returning material to the interstellar medium that has been enriched in heavy elements and other products of nucleosynthesis (such as carbon, nitrogen, oxygen and calcium). In more distant galaxies, planetary nebulae may be the only objects that can be resolved to yield useful information about chemical abundances. In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. About a fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms which produce such a wide variety of shapes and features are not yet well understood, but binary central stars, stellar winds and magnetic fields may all play a role. Planetary nebulae are generally faint objects, none is visible to the naked eye. The first planetary nebula discovered was the Dumbbell Nebula in the constellation of Vulpecula, observed by Charles Messier in 1764 and listed as M27 in his catalogue of nebulous objects. To early observers with l - Besorgungstitel - vorauss. Lieferzeit 3-5 Tage.., [SC: 4.00]<

2012, ISBN: 1155252071

Kartoniert / Broschiert SCIENCE / Astronomy, mit Schutzumschlag neu, [PU:Books LLC, Reference Series]