|MadSci Network: Astronomy|
The elements in a star are identified using the technique of spectroscopy. The analysis of the radiation (light) coming from a star will identify the elements in that star. A great place to start looking for information about this is NASA Spacelink. Go to the bottom of the page and enter your question in the "Search" box. Some of the information that you will be referred to includes: Spectra and Spectroscopy Spectra and What Scientists Can Learn From Them John Haberman, Space Scientist NASA Goddard Space Flight Center
Try the links in the MadSci Library for more information on Astronomy.