Caption: Relatively low-mass stars like the sun end their lives by shedding most of their outer layers as a nebulous cloud, leaving behind a tiny, hot star. Many stars puff off their gas in a spherical shell, superficially resembling the disc of a planet, hence the name for this class of object. In some cases, as in NGC 6302, the gas has expanded unevenly and an irregular planetary nebula results. In this example, some of the gas was ejected from the star at speeds of around 400 kilometers per second, indicating a particularly violent initial explosion.
Copyright: (c) 1977 Anglo-Australian Telescope Board, photograph by David Malin
