Download HR DIAGRAM ACTIVITY

HONORS EARTH SCIENCE
HR DIAGRAM ACTIVITY
NAME _________________
DATE _______ HOUR ___
The Hertzsprug- Russel diagram (H-R) is a graph where a star’s temperature is plotted against its
brightness. From this diagram you can determine star properties as well as its life stage
I.
Purpose
To classify stars
II.
Materials
Star chart, graph, colored pencils
III.
Procedure
1. Determine the color of each star from the temperature-color chart. Record colors on the table.
2. Plot each star on the grid. Use colored pencils to indicate the star’s color. For white stars, use a gray
pencil. Notice the graph lines are not evenly spaced. Label each star name.
IV. Observations
Star
Brightness
(L)
Temperature
(ºC)
Color
Regulus
Polaris
Beta-Centauri
Achernar
Antares
Spica
Aldebaran
Betelgeuse
Arcturus
Vega
160
5500
1700
1000
910
760
160
16000
100
50
13600
5400
25100
17400
3200
24400
3600
3100
4500
11300
Lt. Blue
Star
Brightness
(L)
Temperature
(ºC)
0.025
12
10
.01
2
1
0.4
0.1
0.03
0.01
25600
9600
8400
9000
6100
5570
5600
4400
3500
16000
Sirius B
Formalhut
Altair
Procyon B
Alpha-Centauri
Our Sun
Ceti
Indi
Lacaille 8760
40 Eridani
Color
IV.
Analysis- use pages 627-628 to help you
You can check your HR diagram at: http://deskarati.com/wp-content/uploads/2012/03/HertzsprungRussell-Diagram.jpg
1. Draw a circle around all the red giants on your graph and label this enclosed area Red Giants.
2. Draw a circle around all the white dwarfs and label this enclosed area White Dwarfs.
3. The majority of stars belong to the main sequence group. Draw an ellipse enclosing the points
representing main sequence stars. Label this area Main Sequence.
Temperature
4. Find the Sun on your HR diagram. Draw arrows on the HR diagram showing
the various stages the Sun will go through until the end of its life cycle. (page 632)
5. Of the stars you plotted, which is nearest to the end of its life?
________________ (name of star)
Explain how you determined this.
6. The _______________ (longer or shorter) the wavelength, the hotter the star.
(C)
> 25,000
11,00024,999
7,500-10,999
6,000-7,499
5,000-5,999
3,500- 4,999
2,000- 3,499
Color
Dark Blue
Light Blue
White
Light Yellow
Yellow
Orange
Red
7A. Is luminosity more similar to absolute or apparent magnitude? (think about where the sun is) Explain.
7B. If you put Spica and the Sun next to each other at equal distance, which would be brighter? Why?
Use your HR diagram to determine the following: (choose MS, RG or WD)
8. If a star is very hot and very bright, it belongs in this category ___________________
9.
If a star is very cool and very dim, it belongs in this category ___________________
10. If a star is very hot and very dim it belongs in this category ______________________
11. If a star is very cool and very bright, it belongs in this category __________________
12. Not all red stars are Red Giants. According to the HR diagram, what also has to be true to be
considered a Red Giant?
(use table 23.3 on page 638 to help you)
13. In the main sequence, the most massive stars are what color?
The least massive stars are what color?
14. Look at the main sequence stars on your HR diagram, which main sequence star is the most massive?
15. Complete the sentence. For main sequence stars: The ______ the temperature the _______ the
(higher or lower)
(higher or lower)
luminosity the ______ massive the star
(more or less)
16. On the HR diagram to the left, fill in the boxes with the
following terms: hot bright, cool bright, hot dim, cool dim
Bonus: Why are there no green stars? (you need to research this)
Here’s a great website (I’ll link it on my website) to help with the HR diagram. Scroll down and click on
the Interactive version with questions: http://aspire.cosmic-ray.org/labs/star_life/hr_interactive.html
If you can get 12-13 questions correct, you really understand the HR diagram !