Science 8
Unit 2
Astronomy
Name: ___________________________________________
Date: _______________________ Period: ______________
LAB- Using a Hertzsprung-Russell (HR) Diagram
Purpose: To understand the relationships between a star’s color, temperature and brightness.
Materials: HR Diagram, colored pencils
Procedure:
1. Using the data in the table, plot the location of each star and label it with its name.
2. Complete the data table based on the location of the star on the HR Diagram.
3. Color the columns of the HR Diagram.
4. Answer the questions.
Background:
The Hertzsprung-Russell Diagram is actually an elaborate graph that illustrates the relationship
that exists between the average surface temperature of stars and their absolute magnitude. Absolute
magnitude is how bright stars would appear to be if they were all the same distance away from Earth.
Rather than speak of brightness of stars we often use the word “luminosity.” Luminosity of stars is affected
by both the temperature and size of the star. The most luminous stars would be large and hot. The color of
a star is a direct reflection of the surface temperature, which is illustrated in the diagram.
Star Name
1
2
3
4
5
6
7
8
9
10
11
12
Shaula
Gacrux
Castor
Adhara
Betelgeuse
Canopus
Gamma Cygni
Sol
Tau Ceti
VMS-2
Wolf 424B
Epsilon Indi
Absolute
Magnitude
-3.5
-1.2
0.5
-4.8
-7.2
-2.5
-5.1
4.8
5.75
14.2
15.2
6.16
Spectral
Class
B2
M4
A2
B2
M2
A9
F8
G2
G8
A7
M5
K2
Color
Surface
Temperature
Star Type
(Size)
Analyze and Conclude:
1. What is the temperature for the following stars?
a. Castor __________
b. Sol
__________
c. Canopus
__________
d. VMS-2 __________
2. If Polaris (The North Star) coordinates were G6, -7 what would it’s color, temperature and star type
be?
a. color __________
b. temp. __________
c. type __________
3. Name on giant star and its attributes (color, temp., type)
a. name ____________________
b. color __________
c. temp. __________
d. type __________
4. Compare the brightness of a white dwarf to any stars in the main sequence.
______________________________________________________________________________
5. Where are the white dwarfs found on the HR Diagram? (class and coordinates)
______________________________________________________________________________
6. Name the hottest star on the chart.
____________________
7. What color are the hottest stars?
____________________
8. What color are the coolest stars?
____________________
9. Rigel is at the coordinates B9, -10.5. Describe this star.
a. color __________
b. temp. __________
c. type __________
10. Compare and contrast Mira to Canopus (Mira is at M5, -5).
______________________________________________________________________________
11. Compare and contrast Shaula to EI (EI is at K2, +4).
______________________________________________________________________________
12. What is the approximate surface temperature of our sun (Sol)?
__________
13. Most of the stars shown on the HR Diagram are classifies as what kind of stars? ______________
14. How is it possible for the white dwarfs to have a lower luminosity than the sun even though the sun
is much cooler than the white dwarfs?
______________________________________________________________________________
15. Would the surface temperatures of stars classified as giants generally be higher or lower than
white dwarfs? ________________________________________