W-Ursae-Majoris-Type Light Curve ( Binary Stars)
This group of stars, of which the prototype is W Ursae Majoris, are binary stars that are so close together that they are in contact. The binary system consists of two stellar cores, orbiting around one another, surrounded by a common envelope. Again, the light curve varies smoothly around the cycle often varying from cycle to cycle. The two minima are almost exactly equal, even though the two stellar cores may have different masses and luminosities.