Download The Hertzsprung – Russell Diagram

Name: _____________________________
Period: _____
The Hertzsprung – Russell Diagram
Background Information:
For astronomers, a graph that displays a star’s luminosity on the y-axis and its surface temperature on the x-axis
sets up an extremely useful diagram called a Hertzsprung-Russell, or H-R Diagram. In 1910 Ejnar Hertzsprung
and Henry Norris Russell discovered that when all of the known stars were put on their graph, several obvious
groups became apparent. By examining the differences in these groups, later astronomers were able to realize
that the groups were best described as stars in different periods in their life cycle, rather than completely
different types of stars. Just as infants, adolescents and adults are in different stages of the human life cycle,
main sequence, red giants, super-giants and white dwarfs are stars in different stages of the life cycle of stars.
Color the H-R Diagram below to show the temperature of the stars.
1. What information is plotted on the vertical axis of the diagram?
2. What information is plotted on the horizontal axis of the diagram?
Pre-AP Astronomy
3. List the colors of the stars from the color of the hottest star to the color of the coolest star.
4. List the four categories of information you can determine about a star by using the H-R Diagram?
5. If you know a star’s color, what other information can you determine?
6. What is the relationship between the X and Y values for main sequence stars?
7. 90% of stars belong to which category?
8. Which star is the brightest white dwarf?
9. What star is the hottest super giant?
10. What is the temperature of Barnard’s Star?
11. Which star is the dimmest on this chart?
12. In which category will you find the hottest star on the chart?
13. What category of stars are hot but not very luminous?
14. Compare our Sun to Alpha Centauri A in terms of group, brightness, color and temperature.
15. Compare Zeta Eridani to Epsilon Eridani in terms of group, brightness, color and temperature.
16. Describe the ways in which Barnard’s Star and Antares are alike.
17. Place the following stars in order of increasing temperature:
Alpha Centauri A, Betelgeuse, Rigel and Sirius B
__________________  __________________  __________________  __________________
18. Place the following stars in order of increasing brightness:
Rigel, Barnard’s Star, Sirius, and Procyon B
__________________  __________________  __________________  __________________
Pre-AP Astronomy