Name:____________________________ Lab Section Online Date: _____________
Table 1
|
Eggen Catalog Number |
Color Index mb - mv |
Apparent Magnitude mv |
Absolute Magnitude Mv |
Distance Modulus mv - Mv |
|
9 |
|
|
|
|
|
18 |
|
|
|
|
|
20 |
|
|
|
|
|
22 |
|
|
|
|
|
27 |
|
|
|
|
|
31 |
|
|
|
|
Average Distance Modulus = ________________
Method 2: You may wish to print one of the two graphs onto transparency for this method. You can also use a blank computer screen as a light table if you choose. Place the color-magnitude diagram over the standard Main Sequence plot, aligning the two mb - mv scales. Keeping these scales aligned; slide the top graph up and down until the color-magnitude data best overlay the standard Main Sequence curve. Find the difference between the corresponding values of Mv and mv from the vertical axes of the graphs. This is the distance modulus.
Distance Modulus = ___________________
Questions
1. Calculate the distance to the Pleiades in both parsecs and light-years using the distance modulus values from Method 1 and Method 2 (show your work).
a. distance modulus (Method 1) ___________
b. 
____________________ = 
c. Distance Factor (
) ________________
(farther than 10 pcs)
d. Distance (Distance factor X 10 parsecs) _______________
Distance __________ parsecs
Distance __________ light-years
e. distance modulus (Method 2) ___________
f. 
____________________ =
g. Distance Factor (
) ________________
(farther than 10 pcs)
h. Distance (Distance factor X 10 parsecs) _______________
Distance __________ parsecs
Distance __________ light-years
2. What assumption is made in determining the distance to a cluster using these methods?
3. How would interstellar gas and dust affect your results?
