SES4U
Grade 12 Earth & Space – University
Name: _____________________________________________
Date: _____________________________________________
HR Diagram Lab
Learning Goals:
 I can use spectral data from stars to classify them
 I can graph temperature and magnitude of stars to determine if a relationship exists
 I can sort the number of types of stars to determine if they are evenly distributed
among the different types
Purpose:
To determine the relationship between the Spectral Type of a star (temperature)
and its absolute magnitude (MV).
Hypothesis:
a. If the temperature of a star increases then the absolute magnitude will decrease.
b. If the temperature of a star increases then the absolute magnitude will increase.
Procedure:
1) Goto: http://scope.pari.edu/science.php (goal: understand what is solar spectral
data)
2) Answer the question sheet provided.
3) Goto: http://scope.pari.edu/takepart.php#Tools (goal: learn to classify stars
using spectra)
4) Goto: http://scope.pari.edu/index.php you will need to “sign-up” (top left
corner).
a. Select “Classify” from the top menu. The page that comes up should be
(http://scope.pari.edu/panelchooser.php)
b. Single click on one spectra from the image.
c. Double click on the Spectral Type Spectrum, at the bottom of the screen,
that you think best matches your star.
d. Use the right and left arrows to adjust the ‘alignment’ of the spectra to the
reference. A match of 9/10 or 10/10 is best.
e. Determine the “next level” or sub-level of spectral classification (ie: B8III
or for at least three of your stars. For the rest a classification of O or M or
A is acceptable.
5) Graph the results using Table A.
6) Sort the results using Table B
SES4U
Grade 12 Earth & Space – University
Name: _____________________________________________
Date: _____________________________________________
Table A: Observations
Vela AL
Vela BC
Plate
HD
HD72648
HD72919
HD72876
HD73568
HD73153
HD73010
HD72675
HD73477
HD73367
HD73326
HD72817
HD73739
HD72900
HD72752
V* T Vel
HD73461
HD73244
HD72800
HD73478
HD73220
HD72939
HD73608
HD72286
HD72975
HD72349
HD72555
HD72179
HD71470
HD71787
CD-44 4392
HD72232
HD71743
HD71444
HD72351
HD72140
HD71984
HD72017
HD71509
HD72253
HD72090
MV
-1.54
-1.33
2.43
-7.42
0.14
-1.82
3.28
2.48
-0.20
1.88
-7.40
-2.56
-0.03
-3.36
1.49
0.49
-7.51
-2.46
1.41
6.80
2.68
-1.22
1.68
0.48
4.79
-0.55
0.78
4.12
-0.40
2.08
-4.07
-0.15
-1.27
Spectral Type
Vela SK
Vela MA
SES4U
Grade 12 Earth & Space – University
HD71587
HD71218
HD71237
HD71125
HD70872
HD70781
HD70506
HD69883
HD70717
HD70218
HD69931
HD70850
HD70967
HD70507
HD70142
V* IT Vel
HD70766
HD70729
HD70238
CD-48 3728
HD70799
HD69729
HD69781
HD69822
HD69762
HD69650
HD68805
V* Al Vel
HD68322
HD68786
HD68604
HD69130a
HD69404
HD69109
V* AH Vel
HD68555
V* BN Vel
HD68966
HD68419
HD68187
HD68157
Name: _____________________________________________
Date: _____________________________________________
1.87
3.62
0.39
5.70
-0.79
-0.06
0.67
0.33
4.69
4.11
5.22
0.28
-0.87
4.99
-4.62
1.46
-1.01
4.95
3.92
2.50
1.34
1.64
4.93
1.55
5.92
-1.55
7.45
-2.28
4.20
1.13
4.74
Hydra-2 SK
Hydra-2 MA
Hydra-2 AL
Hydra-2 BC
SES4U
Grade 12 Earth & Space – University
HD68092
HD97663
HD97877
HD97864
HD97717
HD98019
HD97751
HD97573
HD97342
HD97309
HD97444
HD97426
HD97505
HD96745
HD96838
HD96800
HD96874
HD96766
HD96403
HD96030
HD96276
HD96050
HD95680
HD95425
HD95562
HD95282
HD95180
HD94838
HD95384
HD95194
HD95145
HD95580
HD95315
HD95158
HD94839
Name: _____________________________________________
Date: _____________________________________________
-1.00
1.01
5.12
2.08
5.04
0.66
2.00
2.40
4.30
1.95
6.42
1.13
-0.19
0.93
0.71
7.11
1.73
2.47
4.31
2.31
1.43
6.84
1.51
1.96
2.07
4.80
-4.94
0.94
2.72
1.53
Table B: Distribution of Stars across the different types
Spectral
O
B
A
F
Type
Number
of Stars
%
G
K
M
SES4U
Grade 12 Earth & Space – University
Analyze:
Name: _____________________________________________
Date: _____________________________________________
SES4U
Grade 12 Earth & Space – University
Name: _____________________________________________
Date: _____________________________________________
Conclusion:
Write a conclusion for this lab activity. Use the success criteria below to help structure your
response.
Success Criteria
 Paragraph form
 Hypothesis is accepted or rejected
 Evidence from lab is used to support reasoning for accepting or rejecting hypothesis
 Summarize the relationship between the spectral type of star (temperature) and the
Absolute Magnitude of the stars. Is the distribution random or uniform?
 For this set of data, what are the most common type of stars? What factors could
affect the distribution of different spectral types of stars.
 Outline any outliers that exist in the graph. Discuss reasons for these outliers