Albireo

Albireo is a double star found in the constellation Cygnus ("the swan"). It is considered the "beak star", located at the head of the swan; as the second-brightest star in Cygnus, it is also known as Beta Cygni (β Cyg). When viewed with a telescope, it readily resolves into a double star, one yellow (apparent magnitude 3.1), the other blue (apparent magnitude 5.1), providing one of the best contrasting double stars in the sky. The pair is located 385 light years away, and initially it was believed that the stars were merely an optical double, not orbiting around a common point as a true double star system would be. However, in spite of the large distance between them (400 billion miles, or 50 times the diameter of our solar system), it has been shown that they are a true double system, with an orbital period on the order of 100,000 years, a rather stately and sedate dance.

The brighter, yellow member of the pair, Beta Cygni A, is itself a close binary.