Planetary Nebulae Clouds

859 WordsFeb 17, 20183 Pages
Nebula or the plural nebulae is derived from the Latin word for cloud(s), and is a term traditionally used by astronomers to describe the vast gaseous structures which exist throughout the universe. Nebulae now have been divided into five major categories due to their reflective and observational characteristics, these being emission nebulae, reflection nebulae, dark nebulae, supernova remnants and planetary nebulae. In fact, the term planetary nebula is a misnomer as they have nothing to do with planets or planetary systems as the name was derived by eighteenth-century astronomers, William Herschel et al, who due to the restrictions of observational technology available at that time i.e. small telescopes first thought they either looked like the gas-giant planets of our solar system or stars forming new planetary systems. Planetary nebulae are often given the connotation PN or PNe for the plural by astronomers and exhibit the final stage of a star's life whose initial size is approximately between 1 and 8 solar masses, where the unused gases and elements left from nuclear fusion are blown away from the remaining core producing a luminous colourful halo around it. These phenomena can be very short lived in astronomical terms, possibly just tens of thousands of years. To reach this final stage of existence all stars go through the same accepted pattern of evolution, except in the case for large mass stars who have much shorter lives due to burning their hydrogen fuel

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