The physical processes which affect the ionization of the outer circumstellar envelope of
Alpha Ori are analyzed and evaluated. The ultraviolet radiation fields of the chromosphere
and the interstellar medium dominate the envelope, and the most common forms of all
species are neutral atoms and first ions. Hydrogen recombines just outside the
chromosphere, where atoms with smaller ionization potential are essentially fully ionized.
The heavier ions gradually recombine with increasing distance from the star, until the�…