If an atom or molecule absorbs enough energy from a photon or a collision, an electron can be ejected . Diferent spectral line signatures. Different chemical properties. Which elements are ionized, in whole or in part. These data give us a nearly complete picture of the physical conditions in the object.
Spectroscopy is one of the most important tools of the astronomer.
2001 February 3 Copyright Richard W. Pogge, All Rights Reserved.