Susan Imig, age 11, of Zffauwatosa, Wis., for her question:
Why do the stars twinkle with different colors?
It takes a sharp eye to spot the various colors of the stars. They are so fairy like that it is easy to think we imagined them. Actually, the stars do come in assorted colors. Much of the color is blurred by distance and much more by our hazy atmosphere. We see the heavens through a gauzy veil of fir: Out in deep space, we are told, the countless stars glow with vivid colors.
An astronomer can tell a great deal about a star from its color. For the stars have been classified according to types and all the stars of a certain type are the same color. Our sun is rated as a yellow star and other yellow stars are usually about the same size, more or less the same temperature and they contain mainly the same elements.
The types of stars are named with letters. The giants and super giants are M type stars. Some of these whoppers are big enough to swamp almost half of our Solar System. They glow with a red light and, as stars go, they are cool. The surface temperature ranges around 5,500 degrees Fahrenheit. Betelguese, the big red star in. the constellation Orion, is one of these red giant M type stars.
K type stars are smaller, hotter and orange or orange red in color. Their surface temperature is around 7,500 degrees Fahrenheit. Aldebaran, the bright orange red star in the constellation Taurus, is a K type star. Our glorious sun is rated as a G type star. Its surface temperature is about 11,000 Fahrenheit degrees and, compared with other stars out in space, it shines with a golden yellow light. F type stars are yellowish white. Their surface temperature ranges around 13,500 degrees Fahrenheit.
Procyon, the bright star in Canis Zinor, is an F type star.Sirius, the Dog Star, is rated as an A type star. Its surface temperature is almost twice as high as that of our sun and it sparkles with a diamond white light. An example of a B type star is Rigel, also in the constellation Onion. The surface temperature of this type of star is around 36,000 Farrenheit degrees and it twinkles with a blue white light.
You can spot examples of there star types in a group of constellations which follow each other over the winter sky. Taurus, the Hull, rises early with Aldebaran,, a red orange K type star. Onion, the Hunter, follows with the red giant Betelguese high above the three stars in the hunters belt and Rigel, a blue white B type star far below the belt. Next cones Sirius, a white A type star in the Big Dog Constellation. Procyon, a yellow white F type star is in the Little Dog Constellation somewhat higher in the sky.