Matches in DBpedia 2015-10 for { <http://dbpedia.org/resource/Planetary_nebula> ?p ?o }
- Planetary_nebula abstract "A planetary nebula, often abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding glowing shell of ionized gas ejected from old red giant stars late in their lives. The word "nebula" is Latin for mist or cloud and the term "planetary nebula" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. 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.A mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energises the shell of nebulous gas around the central star, appearing as a bright coloured planetary nebula at several discrete visible wavelengths.Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances.In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. About one-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 play a role.".
- Planetary_nebula thumbnail NGC6543.jpg?width=300.
- Planetary_nebula wikiPageExternalLink ?id=7NfqpZxO_o0C.
- Planetary_nebula wikiPageExternalLink ?id=gDSsAAAAIAAJ.
- Planetary_nebula wikiPageExternalLink ?id=kd4VEZv8oo0C&dq.
- Planetary_nebula wikiPageExternalLink ?id=qTZld_-Y5qYC.
- Planetary_nebula wikiPageExternalLink ?id=uRgWHDGpKZIC.
- Planetary_nebula wikiPageExternalLink ?id=xxVkZBVIZeAC.
- Planetary_nebula wikiPageExternalLink background.
- Planetary_nebula wikiPageExternalLink planetar.html.
- Planetary_nebula wikiPageExternalLink stellar-chemistry-05a.html.
- Planetary_nebula wikiPageExternalLink heic1316a.pdf.
- Planetary_nebula wikiPageExternalLink index.html.
- Planetary_nebula wikiPageExternalLink chap1.pdf.
- Planetary_nebula wikiPageExternalLink planneb.html.
- Planetary_nebula wikiPageExternalLink planetary_nebulae.
- Planetary_nebula wikiPageExternalLink theme3.py?level=1&index1=38478.
- Planetary_nebula wikiPageID "39674".
- Planetary_nebula wikiPageLength "45160".
- Planetary_nebula wikiPageOutDegree "127".
- Planetary_nebula wikiPageRevisionID "677557443".
- Planetary_nebula wikiPageWikiLink Abell_39.
- Planetary_nebula wikiPageWikiLink Absorption_line.
- Planetary_nebula wikiPageWikiLink Andromeda_Galaxy.
- Planetary_nebula wikiPageWikiLink Astronomical_spectroscopy.
- Planetary_nebula wikiPageWikiLink Asymptotic_giant_branch.
- Planetary_nebula wikiPageWikiLink Atmosphere_of_Earth.
- Planetary_nebula wikiPageWikiLink Binary_star.
- Planetary_nebula wikiPageWikiLink Bipolar_nebula.
- Planetary_nebula wikiPageWikiLink Bulge_(astronomy).
- Planetary_nebula wikiPageWikiLink Carbon.
- Planetary_nebula wikiPageWikiLink Category:Articles_containing_video_clips.
- Planetary_nebula wikiPageWikiLink Category:Planetary_nebulae.
- Planetary_nebula wikiPageWikiLink Category:Stellar_evolution.
- Planetary_nebula wikiPageWikiLink Cats_Eye_Nebula.
- Planetary_nebula wikiPageWikiLink Charge-coupled_device.
- Planetary_nebula wikiPageWikiLink Charles_Messier.
- Planetary_nebula wikiPageWikiLink Chemistry.
- Planetary_nebula wikiPageWikiLink Continuum_(measurement).
- Planetary_nebula wikiPageWikiLink Continuum_(theory).
- Planetary_nebula wikiPageWikiLink Cosmic_distance_ladder.
- Planetary_nebula wikiPageWikiLink Density.
- Planetary_nebula wikiPageWikiLink Doppler_effect.
- Planetary_nebula wikiPageWikiLink Doppler_shift.
- Planetary_nebula wikiPageWikiLink Double_star.
- Planetary_nebula wikiPageWikiLink Doubly_ionized_oxygen.
- Planetary_nebula wikiPageWikiLink Dumbbell_Nebula.
- Planetary_nebula wikiPageWikiLink Earths_atmosphere.
- Planetary_nebula wikiPageWikiLink Electron.
- Planetary_nebula wikiPageWikiLink Emission_nebula.
- Planetary_nebula wikiPageWikiLink Emission_spectrum.
- Planetary_nebula wikiPageWikiLink Energy_level.
- Planetary_nebula wikiPageWikiLink Excited_state.
- Planetary_nebula wikiPageWikiLink Fast_Low-Ionization_Emission_Region.
- Planetary_nebula wikiPageWikiLink File:NGC7293_(2004).jpg.
- Planetary_nebula wikiPageWikiLink Forbidden_line.
- Planetary_nebula wikiPageWikiLink Forbidden_mechanism.
- Planetary_nebula wikiPageWikiLink Galactic_Center.
- Planetary_nebula wikiPageWikiLink Galactic_bulge.
- Planetary_nebula wikiPageWikiLink Galactic_center.
- Planetary_nebula wikiPageWikiLink Galactic_plane.
- Planetary_nebula wikiPageWikiLink Galaxy.
- Planetary_nebula wikiPageWikiLink Galaxy_formation_and_evolution.
- Planetary_nebula wikiPageWikiLink Globular_cluster.
- Planetary_nebula wikiPageWikiLink Globular_clusters.
- Planetary_nebula wikiPageWikiLink Helium.
- Planetary_nebula wikiPageWikiLink Henry_Norris_Russell.
- Planetary_nebula wikiPageWikiLink Hubble_Space_Telescope.
- Planetary_nebula wikiPageWikiLink Hydrogen.
- Planetary_nebula wikiPageWikiLink Infrared.
- Planetary_nebula wikiPageWikiLink Interstellar_medium.
- Planetary_nebula wikiPageWikiLink Ionisation.
- Planetary_nebula wikiPageWikiLink Ionization.
- Planetary_nebula wikiPageWikiLink Kelvin.
- Planetary_nebula wikiPageWikiLink Light-year.
- Planetary_nebula wikiPageWikiLink Light_year.
- Planetary_nebula wikiPageWikiLink List_of_planetary_nebulae.
- Planetary_nebula wikiPageWikiLink Magnetic_field.
- Planetary_nebula wikiPageWikiLink Main-sequence.
- Planetary_nebula wikiPageWikiLink Main_sequence.
- Planetary_nebula wikiPageWikiLink Messier_15.
- Planetary_nebula wikiPageWikiLink Messier_22.
- Planetary_nebula wikiPageWikiLink Messier_46.
- Planetary_nebula wikiPageWikiLink Messier_object.
- Planetary_nebula wikiPageWikiLink Metallicity.
- Planetary_nebula wikiPageWikiLink Metastability.
- Planetary_nebula wikiPageWikiLink Milky_Way.
- Planetary_nebula wikiPageWikiLink Monthly_Notices_of_the_Royal_Astronomical_Society.
- Planetary_nebula wikiPageWikiLink Morgan-Keenan_spectral_classification.
- Planetary_nebula wikiPageWikiLink NGC_2818.
- Planetary_nebula wikiPageWikiLink NGC_6441.
- Planetary_nebula wikiPageWikiLink NGC_6543.
- Planetary_nebula wikiPageWikiLink Naked_eye.
- Planetary_nebula wikiPageWikiLink Nanometre.
- Planetary_nebula wikiPageWikiLink Neon.
- Planetary_nebula wikiPageWikiLink Nitrogen.
- Planetary_nebula wikiPageWikiLink Nova_remnant.
- Planetary_nebula wikiPageWikiLink Nuclear_fusion.
- Planetary_nebula wikiPageWikiLink Nucleosynthesis.
- Planetary_nebula wikiPageWikiLink Open_cluster.