August 9, 2012
Alberio! This is a binary star system located about 380 light years from earth. It is believed that the orbital period of the stars around each other is about 100,000 years. As you can see, each of the stars is a markedly different color. As it turns out, the brighter yellow star is actually itself a very close binary system with two stars going around each other. The color of the stars tells us a lot about the stars. From just this picture we can tell that the blue star is much hotter than the yellow star.