EXERCISES
and DATA SHEET:
1. Print out the HR diagram
chart:
The vertical axis of the
diagram is the Absolute Magnitude, M.
The scale will start at the top with a –10 and increase downward to a +20. Each horizontal line is separated by 1. For example, the lines above the -5 line are
-4, -3, -2, and -1.
The horizontal axis of the diagram is the Spectral Types: O0, B0, A0, F0, G0,
K0, M0.
Each small line is two
larger in number. In other words the
vertical lines to the right of the B0 line in order are B2, B4, B6, and B8.
2.
Plot
the data from all three tables. When you
plot use different symbols for the three different tables as follows:
a. Main Sequence (.) connect the dots with a smooth curve (table
1)
b. Nearest Stars (0) note
any stars away from the MS line (table 2)
c. Brightest Stars (*) note any stars away from the MS line (table
3)
Fill in the group
information for the nearest and brightest stars.
MS = main sequence (on
or near the main sequence line),
RG = red giant or giant (above the main sequence line),
SG = super giant (across
the top of the diagram),
WD = white dwarf (lower
left of the main sequence)
3. Once you have finished
plotting use your diagram to answer questions 1 through 5.
Table 1 Standard
Main Sequence
|
Spectral Type |
Absolute Magnitude |
|
O5 |
-5.8 |
|
B0 |
-4.1 |
|
B5 |
-1.1 |
|
A0 |
0.7 |
|
A5 |
2 |
|
F0 |
2.6 |
|
F5 |
3.4 |
|
G0 |
4.4 |
|
G5 |
5.1 |
|
K0 |
5.9 |
|
K5 |
7.3 |
|
M0 |
9 |
|
M5 |
13 |
|
M8 |
17.8 |
Table 2 The
Nearest Stars to the Sun
|
Star Name |
Apparent Mag, m |
Absolute Mag, M |
Spectral Type |
Distance, pcs |
Group |
|
Proxima Centauri |
11.1 |
+15.4 |
M5 |
1.31 |
|
|
a Centauri A |
0.1 |
+4.4 |
G2 |
1.35 |
|
|
a Centauri B |
1.4 |
+6.7 |
K0 |
1.35 |
|
|
Barnard's star |
9.5 |
+14.2 |
M5 |
1.81 |
|
|
Wolf 359 |
13.5 |
+16.7 |
M8 |
2.35 |
|
|
Lalande 21185 |
7.5 |
+10.5 |
M2 |
2.52 |
|
|
Luyten 726-8A |
12.5 |
+15.3 |
M5 |
2.60 |
|
|
Luyten 726-8B |
13.0 |
+15.8 |
M6 |
2.60 |
|
|
Sirius A |
-1.5 |
+1.4 |
A1 |
2.65 |
|
|
Sirius B |
8.7 |
+10.0 |
A0 |
2.65 |
|
|
Ross 154 |
10.6 |
+13.3 |
M4 |
2.90 |
|
|
Ross 248 |
12.3 |
+14.8 |
M6 |
3.13 |
|
|
e inadirE |
3.7 |
+6.1 |
|
3.28 |
|
|
Ross 128 |
11.1 |
+13.5 |
M5 |
3.31 |
|
|
Luyten 789-6 |
12.2 |
+14.6 |
M6 |
3.31 |
|
|
61 Cygni A |
5.2 |
+7.6 |
K5 |
3.38 |
|
|
61 Cygni B |
6.0 |
+8.4 |
K7 |
3.38 |
|
|
α Centauri A |
4.7 |
+7.0 |
K5 |
3.44 |
|
|
β Centauri B |
3.5 |
+5.7 |
G8 |
3.46 |
|
|
Procyon A |
0.4 |
+2.7 |
F5 |
3.51 |
|
|
Procyon B |
10.8 |
+13.1 |
A3 |
3.51 |
|
|
BD+59°1915A |
8.9 |
+11.2 |
M4 |
3.52 |
|
|
BD+59°1915B |
9.7 |
+12.0 |
M5 |
3.52 |
|
|
BD+43°44 A |
8.1 |
+10.3 |
M1 |
3.55 |
|
|
BD+43°44 B |
11.0 |
+13.3 |
M6 |
3.55 |
|
|
CD-36°15693 |
7.4 |
+9.6 |
M2 |
3.58 |
|
|
G51-15 |
14.8 |
+17.0 |
M8 |
3.66 |
|
|
Luyten 725-32 |
11.5 |
+13.6 |
M5 |
3.78 |
|
|
BD+5°1668 |
9.8 |
+11.9 |
M5 |
3.79 |
|
|
CD-39°14192 |
6.7 |
+8.8 |
M0 |
3.85 |
|
|
Kapteyn's star |
8.8 |
+10.9 |
M1 |
3.91 |
|
|
Kruger 60 |
9.9 |
+11.9 |
M3 |
3.94 |
|
|
Ross 614 |
11.1 |
+13.1 |
M4 |
3.98 |
|
|
BD-12°4523 |
10.1 |
+12.1 |
M5 |
4.02 |
|
|
Wolf 424 |
13.4 |
+15.2 |
M6 |
4.27 |
|
Table 3
The Brightest Stars
|
Star Name |
Apparent Mag, m |
Absolute Mag, M |
Spectral Type |
Distance, pcs |
Group |
|
Sirius A |
-1.5 |
+1.4 |
A1 |
2.7 |
|
|
|
-0.7 |
-4.0 |
F0 |
45.0 |
|
|
a
Centauri A |
-0.1 |
+4.4 |
G2 |
1.3 |
|
|
Arcturus |
-0.1 |
-0.3 |
|
11.0 |
|
|
Vega |
0 |
+0.5 |
A0 |
8.0 |
|
|
Capella A |
0.1 |
-0.7 |
G2 |
14.0 |
|
|
Rigel A |
0.1 |
-7.1 |
B8 |
275.0 |
|
|
Procyon A |
0.4 |
+2.7 |
F5 |
3.5 |
|
|
Betelgeuse |
0.4 |
-6.6 |
M2 |
158.0 |
|
|
Achernar |
0.5 |
-3.0 |
B5 |
50.0 |
|
|
b Centauri |
0.6 |
-4.1 |
B1 |
90.0 |
|
|
Altair |
0.8 |
+2.3 |
A7 |
5.1 |
|
|
a
Crucis A+B |
0.8 |
-3.9 |
B1 |
87.0 |
|
|
Aldebaran A |
0.9 |
-0.7 |
K5 |
20.0 |
|
|
Antares |
0.9 |
-5.4 |
M1 |
128.0 |
|
|
Spica |
0.9 |
-3.6 |
B1 |
80.0 |
|
|
Pollux |
1.1 |
+1.0 |
K0 |
10.5 |
|
|
Fomalhaut |
1.2 |
+2.0 |
A3 |
7.0 |
|
|
Deneb |
1.3 |
-7.1 |
A2 |
480.0 |
|
|
b
Crucis |
1.3 |
-4.6 |
B0 |
150.0 |
|
|
Regulus |
1.4 |
-0.6 |
B7 |
25.0 |
|
|
Adhara |
1.5 |
-5.1 |
B2 |
210.0 |
|
|
Castor A+B |
1.6 |
+0.9 |
A1 |
14.0 |
|
|
Shaula |
1.6 |
-3.3 |
B1 |
95.0 |
|
|
Bellatrix |
1.6 |
-3.9 |
B2 |
125.0 |
|
|
Alnath |
1.7 |
-3.2 |
B7 |
95.0 |
|
|
b
Carinae |
1.7 |
-0.4 |
A0 |
26.0 |
|
|
e Orionis |
1.7 |
-7.0 |
B0 |
550.0 |
|
Super Giants:
Giants:
White Dwarfs:
3)
What
differences, if any, are there between the brightest and nearest stars - where
are the stars mostly located in both diagrams, according to their energy
outputs and temperatures?
4)
a. Are the brightest stars seen in the sky also
the stars that are closest to us? (yes or no)
b. Explain why the brightest stars in the sky are
so bright. Is it because they are close
to us, or is it because of something else?
Be specific.
5) Look carefully at the
diagram and state which stars you would expect to be the most common stars in
space. Hint: first decide between the
nearest or brightest stars (i.e. which group contains the most stars) and then,
determine which stars are most common in that group and what their properties
are.