eclipsing binary (eclipsing variable)

Eclipsing binary. The light curve of the prototype eclipsing binary, Algol. (A) Primary minimum. (C) Secondary minimum. (B) Light of the two components combined. A binary or multiple star system whose total brightness varies on a regular cycle because the orbital motion of the member stars causes them to pass one in front of another as viewed from Earth (see illustration). If the two stars in an eclipsing binary are of unequal luminosity, the light curve displays a primary minimum (at A) when the dimmer star passes in front of the brighter one, and a secondary minimum (at C) when the opposite occurs. The best-known example of an eclipsing binary is Algol.