Some tools for digging information out of solar and stellar spectra. When light from the Sun or stars is displayed according to wavelength, the result is said to be a spectrum . Like everything on Earth, the Sun, stars, and other objects out in space are made of atoms. Since there are about 100 different elements, there are also about 100 different kinds of atoms. The center of an atom is its nucleus, which is a collection of protons and neutrons.
Electrons surround the nucleus.
An atom is neutral if it has as many electrons outside the nucleus as protons in the nucleus. But sometimes an atom loses one or more of its electrons. This happens when the atom is bumped by something with enough energy to kick the electrons out. In the outer atmospheres of the Sun and stars, which are quite hot, the atoms all move fast and get bumped very hard. This causes most of the atoms to lose some of their electrons.