Fraunhofer Lines



  • Absorption lines in the spectrum of the Sun’s photosphere, first observed by the Englishman William Wollaston (1766–1828) in 1802 and later mapped in detail by Joseph von Fraunhofer, (1887–1826), a German physicist. The lines are caused by the removal of energy from the Sun’s radiation by a layer of the Sun’s atmosphere a few hundred kilometres deep above the photosphere. Analysis of the strength of some of the many thousands of Fraunhofer lines has given detailed data about the elements present there and their abundances as well as data about temperatures and magnetic fields.