Many of the stars shine with colored light, as red, blue, green, or
yellow.
These colors are exhibited in striking contrast in many of the double
stars. Combinations of blue and yellow, or green and yellow, are not
uncommon; while in fewer cases we find one star white and the other
purple, or one white and the other red. In several instances each star
has a rosy light.
The following are a few of the most interesting colored double stars:
Color of Color of Smaller
Name of Star Larger One One
γ Andromedæ Orange Sea-Green.
α Piscium Pale Green Blue.
β Cygni Yellow Sapphire Blue.
η Cassiopeiæ Yellow Purple.
σ Cassiopeiæ Greenish Bright Blue.
ζ Coronæ White Light Purple.
ι Cancri Orange Blue.
α Herculis Orange Emerald Green.
Single stars of a fiery red or deep orange color are common enough. Of
the first color may be mentioned Aldebaran, Antares and Betelgeuse.
Arcturus is a good example of an orange star. Isolated stars of a deep
blue or green color are very rarely found; among the conspicuous stars,
β Libræ appears to be the only instance.
It is now a well-established fact that the stars change their color.
Sirius was described as a fiery red star by the ancients, is now decided
green color.
=NAMES OF IMPORTANT STARS=