The Hertzsprung - Russell Diagram

The Hertzsprung-Russell (HR) diagram is actually a graph that illustrates the relationship that exists between the average surface temperature of stars and their absolute magnitude, which is how bright they would appear to be if they were all the same distance away.

The brightness of stars is affected by temperature and size. The brightest stars would be those that are large and hot. The least bright stars would be small and cool. The color of a star is determined by its surface temperature, which is illustrated on the HR diagram.

Using the HR diagram above, answer the following questions.

1. What is the approximate surface temperature of the sun? ______

2. Would the surface temperature of the stars classified as white dwarfs be generally higher or lower than that of the stars classified as supergiants? ______3. a. What is the color of the stars show on the diagram that have the highest surface temperature?______

b. What is the color of the stars shown on the diagram that have the lowest surface temperature?______

c. List the colors of the stars from the color of the hottest star to the color of the coldest star:

Color of hottest star

Color of coldest star

4. Most of the stars shown on the diagram are classified as which type of star? ______

5. Our sun is classified as which type of star? ______

6. a. Which is brighter, the Sun or Albdebaran? ______

b. Which is hotter, Sirius B or Betelguese? ______