Eclipsing binary

A binary star system in which chance alignment of the orbits mean that, from Earth, the stars periodically pass in front of one another causing eclipses . The result of this is that the combined light of the stars varies and give the binary the appearance of a variable star. A good example of this is the star Algol in the constellation of Perseus. The two components in this system orbit one another with a period of 2.87 days. Being a star visible to the naked eye means that even casual observers can see when the Algol system is in eclipse because it is noticeably dimmer in the night sky.