Beta Cephei variables are variable stars which exhibit variations in their brightness due to pulsations of the stars' surfaces. The point of maximum brightness roughly corresponds to the maximum contraction of the star. Typically, Beta Cephei variables change in brightness by 0.01 to 0.3 magnitudes with periods of 0.1 to 0.6 days. Most stars are of nearly constant luminosity. ...

The prototype of these variable stars, Beta Cephei shows variation in apparent magnitude from +3.16 to +3.27 with a period of 4.57 hours. The apparent magnitude (m) of a star, planet or other heavenly body is a measure of its apparent brightness; that is, the amount of light received from the object. ...

These stars should not be confused with Cepheid variables, which are named after Delta Cephei. A Cepheid variable is a member of a particular class of variable stars, notable for a fairly tight correlation between their period of variability and absolute stellar luminosity. ... Delta Cephei (δ Cep / δ Cephei) is a star in the constellation Cepheus. ...

References

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