gas-bounded nebula An interstellar cloud that is kept more-or-less completely ionized by one or more hot, luminous stars within it. The visible extent of the nebula is thus limited by the actual size of the cloud and the quantity of material it contains, rather than in the case of a radiation-bounded nebula, where the limiting factor is the amount of ionizing radiation available. Related category • NEBULAE AND STAR CLUSTERS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |