Rotating ellipsoidal variable

Rotating ellipsoidal variables are a class of variable star. They are close binary systems whose components are ellipsoidal. They are not eclipsing, but fluctuations in apparent magnitude occur due to changes in the amount of light emitting area visible to the observer. Typical brightness fluctuations do not exceed 0.1 magnitudes.

The brightest rotating ellipsoidal variable is Spica (α Virginis).

References

Morris, S.L. "The Ellipsoidal Variable Stars", ApJ 295: 143-152, 1985 August 1

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