Gamma Cassiopeiae variables are variable stars which exhibit irregular variations in their luminosity due to the outflow of matter from the star. They are typically spectral type B main sequence or giant stars and the brightness fluctuations can be as large as 1.5 magnitudes. Most stars are of nearly constant luminosity. ... An irregular variable is a type of variable star in which variations in brightness show no regular periodicity. ... // In General Physics In general physics, luminosity (more properly called luminance) is the density of luminous intensity in a given direction. ... The Pleiades star cluster A star is a massive body of plasma in outer space which is currently or has in the past produced energy through nuclear fusion. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequenly refined in terms of other characteristics. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... According to the Hertzsprung-Russell diagram, a red giant is a large non-main sequence star of stellar classification K or M; so-named because of the reddish appearance of the cooler giants. Examples include Aldebaran and Arcturus. ...

The namesake is Gamma Cassiopeiae.

References

Samus N.N., Durlevich O.V., et al. Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.)