Download H-R Diagram Student

Name___________________________________________
H-R Diagram
The Hertzsprung-Russell diagram is actually a graph that illustrates the relationship that exists
between the average surface temperature of stars and their______________ ______________,
which is how bright stars appear to be if they were all the same distance away. Rather than
speak of the brightness of stars, the term luminosity is often used. ______________________is
a measure of how much energy leaves a star in a certain period of time. The luminosity of
stars is affected by temperature and size.
Increasing Absolute Magnitude
(Brightness)
Step 1: Color the different sections of the H-R diagram with the appropriate color.
Increasing Average surface temperature (◦ C)
Step 2: Answer the following questions using the H-R diagram.
1. What is plotted on the y-axis of the graph? _______________________________________
2. What is plotted on the x-axis of the graph? _______________________________________
3. Find the Main Sequence group of stars. What does the H-R diagrams tell us about the
relationship between magnitude and temperature for this groups stars?____________________
_____________________________________________________________________________
4. Name a star that is very dim and red. ____________________________________________
5. Compare our sun to Alpha Centauri A in terms of brightness, color and surface
temperature.___________________________________________________________________
_____________________________________________________________________________
6. Describe the ways in which Bernard’s Star and Antares are alike. ____________________
_____________________________________________________________________________
_____________________________________________________________________________
7. Describe three features of the star Deneb. _______________________________________
_________________________________________________________________________
8. How would you classify the star Deneb? ________________________________________
9. If you walked out on a clear night and looked for the star Aldebaran, what clues would you
use to identify it? ______________________________________________________________
_____________________________________________________________________________
10. Would the surface temperature of the stars classified as white dwarfs be generally higher of
lower than that of the stars classified as supergiants? _________________________________
____________________________________________________________________________
11. What is the color of stars that have the highest surface temperatures?__________________
12. The lowest?_____________________
13. Sequence the color of the stars from the hottest to the coldest.
Hot
_______________
Cold
_______________
_______________
_______________
_______________
14. 90% of all stars are classified as Main Sequence stars.
What is our Sun classified as? __________________________
What is Betelgeuse classified as?_________________________
15. How is it possible for white dwarfs to have a lower luminosity than the Sun even though
the Sun is much cooler than the white dwarf? _______________________________________
_____________________________________________________________________________
Step 3: Use the H-R diagram below to answer the following questions.
16. Which letter correspond to a sun-like star? __________
17. Which letter corresponds to a blue supergiant? __________
18. Which letter corresponds to a white dwarf? __________
19. Which letter corresponds to w red supergiant? ___________
20. Which letter corresponds to an old star that was once a sun-like, main sequence star? ___________
Step 4: Use the terms in the word box below to write a summary paragraph on why the H-R diagram is useful
to astronomers?
color
wavelength
energy mass
temperature brightness