Name:
Astronomy, H-R diagrams
Analyzing, interpreting, and applying information from graphs.
1. First, go to http://aspire.cosmic-ray.org/labs/star_life/hr_diagram.html and
answer the questions there.
Use your own H-R diagram to answer the following questions. One or two word
answers are fine.
2. What is the dimmest star on your diagram?
3. What color are the coolest stars?
4. What star is the hottest supergiant?
5. What is the brightest white dwarf star?
6. Which group of stars is the brightest?
Use your diagram, a diagram from class, and/or your notes to answer the questions
below. Complete sentences are required.
7. If two stars have the same brightness, does that mean they are the same
temperature? Why or why not?
8. If two stars have the same color, does that mean they have the same
temperature? Why or why not?
9. Describe the relationship between these temperature and luminosity for
stars on the main sequence.
10. Describe the ways in which Betelgeuse and Barnard’s Star alike. Describe
how they are different.
11. Compare our sun to alpha Cen A in terms of brightness, color, and
temperature.
12. Write a paragraph summarizing why the H-R diagram is useful to
astronomers. Use key words such as color, energy, temperature, and
brightness.
13. Summarize the difference between apparent magnitude and absolute
magnitude. Why is it important to use absolute magnitude for an H-R
diagram?
Look at the H-R diagram below which has two different scales for the y-axis—a
luminosity scale and a magnitude scale. (Complete sentences not needed)
14. What is the approximate absolute magnitude of Achemar?
15. If a star has a luminosity of 104, about what would you expect it’s absolute
magnitude to be?
16. Which star is brighter—a star with an absolute magnitude of -5.3 or a star
with an absolute magnitude of 6.7?
Other graphs use two axes to show different measurement scales as well.
17. What is the approximate temperature on June 1st in Fahrenheit? In Celsius?
18. Look at the Engine 5 line. 2.5 seconds before the launch, what was the thrust of
the engine in kiloNewtons? In pounds of force?