Download H-R Diagram - Faculty Website Listing

Name
Class
Phys1403
HR Diagram
Part 1: Instructions
Please read the section in textbook that talks about HR diagram. We have also discussed this in class with examples. It
may be useful to have your class notes with you when you do the lab. You can also look them up on the class webpage.
1. Using Stellarium software to collect the information on absolute magnitude and spectral type of a star to plot an H-R
diagram and answer the questions:
2. This Lab will be done in Science room 208. Find one of the available computer stations. Login with your Tarleton ID
and fire up Stellarium from Astronomy Apps.
3. The Spectral Type and Absolute Magnitude of the star can be searched in Stellarium using the Hipparcos Catalog
Number. Using the given Hipparcos catalog numbers in Table 1 below, search and select each star in the list below
by opening the search window (CTRL-F or the F3 button) and typing the letters HP and then the Hipparcos catalog
number, and then pressing Enter to select and center the star and display the information on the star.
4. In the information that appears on screen, the star's Absolute Magnitude is listed on the second line of information,
and its Spectral Type is listed on the third line from the bottom. Use this information to fill in the blanks in Table 1
below. Keep only the first UPPER CASE letter and the subsequent number in the Spectral Type listing – ignore any
Roman Numerals or letters after the numbers. Note that a few stars have been already entered for you.
5. Note that some of the data has already been provided to you. Submit the worksheet after you finish with questions
in part 3
Part 2: Collecting Data
Table 1
#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Star Name
Sirius A
Vega
Castor
Deneb
Fomalhaut
Altair
Procyon B
Canopus
Alnilam
Acrux
Hadar
Spica
Mimosa
Adhara
Shaula
Sirius B
Achernar
Rigel
Regulus
Van Maanen 2
Procyon
Capella
Hipparcos Catalog Number Spectral Type
32349 A0
91262
36850
102098
113368
97649
A8
30438
26311
60718
68702 B1
65474
62434 B1
33579 B1
85927
B2
7588 B6
24436
49669 B8
3829 F0
37279 F5
24608 G1
1
Absolute Magnitude
1.44
1.72
13
-5.48
-3.92
-3.97
11.2
-2.7
14.2
2.68
-0.54
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
Rigel Kentaurus
Alpha Cenbtarui B
Pollux
Arcturus
Aldebaran
Antares
Gacrux
Betelgeuse
Barnards Star
Sun
Proxima
Alpha Centauri A
Alpha Centauri B
Barnard's Star
Kapteyn's Star
Lalande 21185
Sirius A
BD+68 946
Wolf 1061
Kruger 60 A
Ross 154
Van Maanen 2
Epsilon Eridani
Ross 128
Luyten's Star
Epsilon Indi
61 Cygni A
61 Cygni B
Procyon A
Lacaille 8760
Groombridge 34
Lacaille 9352
Tau Ceti
Ross 614 A
Luyten 725-32
71683 G2
G2
37826
69673
21421
80763
61084 M3.5
27989 M4
M5
G2
70890
71683
71681 K2
87937 M4
24186
54035
32349
86162 M4
80824
110893
92403
3829 A2
16537
57548
36208
108870
104214
104217
37279
105090 M1
1475
114046
8102
30920
5643 M6
2
4.45
5.72
-5.1
-5.47
13.23
4.7
Part 3: Plotting Data
Plot the date from table 1 in the graph provided below.
Analysis
1) The Sun has been plotted for you. Circle the group of stars that are part of the Main Sequence, Red Giants
Supergiant’s and White Dwarfs
2) Draw a straight line on the graph that will divide the stars in two groups, one less massive compared to Sun and one
more massive compared to Sun. Hint we have discussed this in class.
3) Draw a straight line on the graph that will divide the stars in two groups, one smaller in radius compared to the Sun
and one larger in radius compared to the Sun. Hint we have discussed this in class.
4) The Sun has been plotted for you. Circle the group of stars that are part of the Main Sequence, Red Giants
Supergiant’s and White Dwarfs
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Part 3: Questions
1) List the similarities and difference between Capella and Sun.
2) Explain why are White Dwarf stars’ dimmer as compared to Main Sequence stars.
3) Choose one of the White Dwarf Stars. Calculate its radius in terms of the Sun’s radius. Hint we have done an
example in class, see the PowerPoint notes on class webpage. Show your work in detail.
4) Choose one of the Red Giant stars. Calculate its radius in terms of the Sun’s radius. Show your work in detail.
5) Choose one of the main sequence stars with Luminosity much bigger than the Sun. Calculate its mass. Hint we have
discussed this in class.
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