A FAVORITE OBJECT FOR AMATEUR ASTRONOMERS IS THE DOUBLE STAR ALBIREO , ONE OF ITS COMPONENTS IS A GOLDEN YELLOW AND THE OTHER A BRIGHT BLUE .

Question

WHAT DOES THESE COLORS TELL YOU ABOUT THE RELATIVE TEMPERATURE OF THE BLUER OBJECTS ?

Answer 1

The apparent color of a star correlates with its blackbody temperature, with red being the coolest and blue the hottest.  Hence, in Albireo, we'd expect the blue star to be hotter than its yellow companion.  Albireo is quite a site in a small telescope, with the blue and yellow forming a striking color contrast.