38, 39 ] Absolute Magnitude 33
to any great extent. The stars within a distance of 4 parsecs at present
known are shewn in the following table:
Table IV. The nearest Stars in order of Distance.
Star
Parallax
Visual
Mag.
Absolute
Mag.
Luminosity
Spectral
Type
Mass
(Sun as
unity)
1
Sun
-26-72
4-85
1
GO
1
2
Proxima Centauri
0-765
10-5
14-9
o-oooio
M
—
a Centauri A
0-758
0-33
4-73
1-12
GO
1-14
a Centauri B
0-758
1-70
6-10
0-32
K 5
0-97
3
Munich 15040
0-538
9-67
13-32
0-00041
M 5
—
4
Wolf 359
0-404
13-5
16-5
0-00002
M6
—
5
Lalande 21185
0-392
7-60
10-57
0-0051
M2
—
6
Sirius A
0-377
-1-58
1-30
26-3
AO
2-45
Sirius B
0-377
8-44
11-32
0 0026
A 7
085
7
B.D. -12°, 4523
0-350
10
12-7
0-00072
—
—
8
Innes (llh. 12 m. -57‘2)
0-340
12
14-7
o-oooii
—
—
9
Cordoba 5 h. 243
0-317
9-2
11-7
0-0018
MO
—
10
r Ceti
0-315
3-6
6-1
0-32
KO
—
11
Procyon A
0-312
0-5
3 0
5-5
F 5
1-24
Procyon B
0-312
13-5
16-0
0-00003
—
0-39
12
e Eridani
0-310
3-8
6-3
0-26
KO
—
13
61 Cygni A
0-300
5-6
8-0
0-055
K 7
—
61 Cygni B
0-300
6-3
8-7
0-029
K 8
—
14
Lacaille 9352
0-292
7-4
9-7
0 011
MO
15
Struve 2398 A
0-287
8-7
110
0-0035
M 4
Struve 2398 B
0-287
9-4
11-7
0-0018
M 4
—
16
Groombridge 34
0-282
8-1
10-4
0-0060
M2
—
17
e Indi
0-281
4-7
6-9
015
K 5
—
18
Kruger 60 A
0-256
9-3
11-3
0-0026
M3
0-25
Kruger 60 B
0-256
10-8
12-8
0-0007
M
0-20
19
Oh. 43-9 m. +4-55
0-255
12-3
14-3
0-00017
F
—
20
Lacaille 8760
0-253
66
8-6
0-032
MO
—
Counting the components of binary and multiple systems as separate stars,
we see that 27 stars are known to lie within a sphere of 4 parsecs radius
drawn around the sun as centre. For almost all purposes these 27 stars form
the best sample we can obtain of the stars as a whole, for as soon as we go
further afield than 4 parsecs, certain types of stars are likely to have remained
undiscovered, so that the discovered stars do not form a true sample of the
whole.
On dividing the 27 individual stars into groups according to their absolute
magnitudes, the numbers in the different groups are found to be as follows:
Abs. Mag. 0 <—4 <—> 8 -<—12 -<—> 16 - 5
No. of stars 2 7 10 8
and we notice that stars whose luminosity is less than that corresponding to
if = 4 are distributed fairly evenly amongst the different absolute magnitudes.
J
3