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physical object > natural object > celestial body > Messier object > Dumbbell Nebula |
Dumbbell Nebula comparison table |
Subject | has purpose | has expansion velocity | is part of | is a kind of | has catalog | is an instance of | has synonym | has definition | has distance | has composition | has Messier number |
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Messier object | originally to catalog all objects which could be confused with a comet | celestial sphere | celestial body | Messier catalog | an object assigned a number by Charles Messier | from Earth | |||||
planetary nebula | typically 10 km/s | gas | expanding emission nebula | planetary nebula catalog | emission nebula | An expanding envelope of rarefied ionized gas surrounding a hot white dwarf. The envelope receives ultraviolet radiation from the central star and reemits it as visible light by the process of fluorescence. The planetary nebula stage lasts for less than 50,000 years. During the core contraction that terminates the red-giant stage, the helium-burning shell is ejected at a velocity so high that it becomes separated from the core. Under current theories, a star with a carbon core and a mass greater than 0.6 Msun (but less than 4 Msun) will become a planetary nebula and leave behind a white dwarf. Planetary nebulae are now known to occur in stars less than 4 Msun whose envelope becomes unstable during the hydrogen shell burning stage. | enhanced with heavy elements relative to the interstellar medium | ||||
Dumbbell Nebula | originally to catalog all objects which could be confused with a comet | typically 10 km/s | gas | planetary nebula catalog | Messier object | NGC 6853 | A planetary nebula of large apparent diameter and low surface brightness. | 220 pc | enhanced with heavy elements relative to the interstellar medium | 27 |
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