Figure 4-1 How Stars Lose Mass (a) Antares, the brightest star in Scorpius, is nearing the end of its existence. Strong winds from its surface are expelling large quantities of gas and dust, creating this nebula reminiscent of an Impressionist painting. The scattering of starlight off this material makes it appear especially bright, even at a distance of 604 ly. (b) The planetary nebula Abell 39 is 7000 ly from Earth. With a relatively gentle emission of matter, the central star shed its outer layers of gas and dust in an expanding spherical shell now about 6 ly across. (c) A supernova is the most powerful known mechanism for a star to shed mass. The Crab Nebula, even though it is about 6000 ly from Earth, was visible during the day for three weeks during 1054.