image credits: Lawrence S. Anderson-Huang, The University of Toledo; Mees Solar Observatory; Joachim Köppen Strasbourg/Illkirch/Kiel 2007; image source
Solar Spectrum
The continuous spectrum with dark absorption lines, which is shown twice above, is sunlight, and the emission lines, in the other spectra, are from the elements indicated. Can you match any of these emission lines to absorption lines in the solar spectrum? You can see the whole spectrum in the larger version and in higher resolution.
Spectral Lines
Spectral Lines, from Physics 2000, and the pages that follow it show how observations of spectral lines led to the concept of atomic energy levels. For more on energy levels, see Ohio State's Measuring Light: Spectroscopy. To find out how stars are classified by their spectral type, visit the Sloan Digital Sky Survey's Energy Levels of Electrons and Columbia University's Spectral Classification of Stars.