The Fate Of The Sun
Our four stars illustrate the four possible fates of the stars: black holes, neutron stars, white dwarfs, and red dwarfs. The Sun will end its life as a hot-but-faint white dwarf, an object no larger than the earth, and like a dying ember in a campfire it will gradually cool off and fade into blackness. Space is littered with such dead suns.
In its death throes, five billion years from now, the Sun will engulf Mercury, broil Venus, and wipe every vestige of life off the earth. Alnilam will go much more violently; if it has planets, they will be vaporized by the supernova. In both cases, though, an expanding cloud of gas will be flung into space. This cloud will be rich in heavy elements, and there would be no such thing as iron atoms floating through space were it not for stars like Alnilam that create them in their central furnaces.
Stars form from these cold, dark clouds, and so do any planets that form around the stars. The Sun and its planets are second-generation products of our Galaxy, and much of the material that went into making the Sun, the earth, and you was once in the center of some distant and long-dead Alnilam. The theme begun by those distant stars has been picked up by the present generation, and five billion years from now, the Sun in turn will return some of its products to space. Sometime after that, the cycle will begin anew.
See also Binary star; Brown dwarf; Gravity and gravitation; Nova; Red giant star; Solar activity cycle; Solar flare; Solar wind; Spectral classification of stars; Star cluster; Star formation; Stellar evolution; Stellar magnitudes; Stellar populations; Stellar structure; Stellar wind; Sunspots; Variable stars.
Kaler, James B., "The Brightest Stars in the Galaxy." Astronomy (May 1991): 31.
Terrell, Dirk, "Demon Variables." Astronomy (October 1992): 35.
Jeffrey C. Hall
Science EncyclopediaScience & Philosophy: Spectroscopy to Stoma (pl. stomata)Star - Energy Generation, Stellar Models, Mass: The Fundamental Stellar Property, Four Stars, Variable Stars - The nature of the stars