Gamma Cassiopeiae star

Gamma Cassiopeiae star is a fast-spinning eruptive variable with a BeIII to BeIV spectrum that, at irregular intervals, shows a series of strong, sharp absorption lines accompanied by a fading due the ejection of matter from the equatorial region of the star. The ejected material may settle into a ring (in a variable Be star) or form a shell (in a shell star), and be accompanied by a fading of up to 1.5 magnitude. Well-known examples are Gamma Cassiopeiae itself, the brightest of its type, and Pleione in the Pleiades.