Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization

First Edition

© 1975-1979, 2008 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization, First Edition, Xenology Research Institute, Sacramento, CA, 1979; http://www.xenology.info/Xeno.htm


 

23.2á Experimental Galactic Demography

Where might we expect to find alien life and civilization in nearby extrasolar space? The tables on the following three pages may serve as starting points for discussions of this speculative question.

Table 23.2 lists the 75 brightest named stars in the night sky of Earth.

 


Table 23.2 The 75 Brightest Named Stars in the Night Sky of Earth
(modified after Robinson3086)
Name
Star
Distance
Spectral 
Class
Luminosity Class
   
(light-years)
   
Sol (a Solaris)
0.000016
G2
Main Sequence dwarf
Rigil Kentaurus A a Centauri A
4.38
G2
Main Sequence dwarf
B
B
4.38
K6
Main Sequence dwarf
Sirius a Canis Majoris A
8.7
Al
Main Sequence dwarf
Procyon a Canis Minoris A
11.4
F5
(leaving Main Seq.)
Altair a Aquilae
16.6
A7
(leaving Main Seq.)
Algenib b Hydri
21
G1
Subgiant
Fomalhaut a Piscis Austrini
22.6
A3
Main Sequence dwarf
Vega a Lyrae
26.5
A0
Main Sequence dwarf
Pollux b Geminorum
35
K0
Normal giant
Arcturus a Bo÷tis
36
K2
Normal giant
Denebola b Leonis
43
A3
Main Sequence dwarf
Caph b Cassiopeiae
4S
F2
Subgiant
Capella a Aurigae
45
G8
Normal giant
Castor A a Geminorum A
45
Al
Main Sequence dwarf
            B                        B
45
A5
 
Alderamin a Cephei
52
A7
(leaving Main Seq.)
Menkent (Chart) Theta Centauri
55
K0
Normal giant
Diphda (Deneb Kaitos) b Ceti
57
K1
Normal giant
Ras Alhague a Ophiuchi
58
A5
Normal giant
Megrez d Ursa Majoris
63
A3
Main Sequence dwarf
Al Na’ir a Gruis
64
B5
Main Sequence dwarf
Acamar Theta Eridani
65
A3
Main Sequence dwarf
Kiffa Australis (Zuben Elgenubi) a Librae A
66
A3
 
Aldebaran a Tauri A
68
K5
Normal giant
Alioth Epsilon Ursa Majoris
68
A0
 
Sabik e Ophiuchi
69
A2.5
Main Sequence dwarf
Mirach b Andromedae
76
M0
Normal giant
Hamal a Arietis
76
K2
Normal giant
Alphecca (Gemma) a Coronae Borealis
76
A0
Main Sequence dwarf
Merak b Ursa Majoris
78
Al
Main Sequence dwarf
Atria a Trianguli Australis
82
K2
Normal giant
Regulus a Leonis A
84
B7
Main Sequence dwarf
Miaplacidus b Carina
86
A0
Normal giant
Mizar Zeta Ursa Majoris A
88
A2
Main Sequence dwarf
Alpheratz a Andromedae
90
B9
 
Phecda (Phad) g Ursa Majoris
90
A0
Main Sequence dwarf
Ankaa (Nair al Zaurak) a Phoenicis
93
K0
Normal giant
Alphard a Hydrae
94
K4
Normal giant
Canopus a Carina
98
F0
Supergiant
Mira Omicron Ceti A
103
M6
Giant
Algol b Persei
105
B8
Main Sequence dwarf
Dubhe a Ursa Majoris
105
K0
Normal giant
Kochab b Ursa Minoris
105
K4
Normal giant
Eltanin (Etamin) g Draconis
108
K5
Normal giant
Markab a Pegasi
109
B9.5
Normal giant
Achernar a Eridani
118
B5
Subgiant
Kaus Australis Epsilon Sagittarii
124
B9
Subgiant
Menkar (Menkab) a Ceti
130
M2
Normal giant
Schedar a Cassiopeiae
150
K0
Bright giant
Alkaid (Benetnasch) e Ursa Majoris
210
B3
Main Sequence dwarf
Scheat b Pegasi
210
M2
Bright giant
Gacrux g Crucis
220
M3
Bright giant
Spica (Azimech) a Virginis
220
B1
Main Sequence dwarf
Almach g Andromedae A
260
K3
Bright giant
El Nath b Tauri
300
B7
Normal giant
Nunki s Sagittarii
300
B2
Main Sequence dwarf
Shaula g Scorpii
310
B1
Main Sequence dwarf
Avior A Epsilon Carina A
340
B
 
          B                         B
340
K0
 
Acrux A a Crucis A
370
B1
Subgiant
          B                B
370
B3
 
Ras Algethi a Hercules
410
MS
Bright giant
Albireo b Cygni A
410
K3
Bright giant
Gienah g Corvi
450
B8
Normal giant
Bellatrix g Orionis
470
B2
Normal giant
Becrux b Crucis
490
B0
Normal giant
Agena (Hadar) b Centauri
490
B1
Bright giant
Betelgeuse a Orionis
520
M2
Supergiant
Antares a Scorpii A
520
M1
Supergiant
Alcyone e Tauri
540
B7
Normal giant
Mirfak a Persei
570
F5
Supergiant
Polaris a Ursa Minoris A
680
F8
Supergiant
Adhara Epsilon Canis Majoris A
680
B2
Bright giant
Al Suhail g Velorum
750
K5
Supergiant
Enif Epsilon Pegasi A
780
K2
Supergiant
Rigel b Orionis A
900
B8
Supergiant
Alnilam Epsilon Orionis
1600
B0
Supergiant
Deneb (Arided) a Cygni
1600
A2
Supergiant


 

Table 23.3 gives a complete inventory of all luminous stars within 20 light-years of Sol.

 


Table 23.3 Complete Inventory of Luminous Stars with 20 Light-Years of Sol 
(modified from Mattinson1114)
Star
Constellation
Distance Spectral Class
   
(light-years)
 
Proxima Centauri Centaurus
4.29
M5
a Centauri A Cantaurus
4.38
G2
                  B Cantaurus
4.38
K6
Barnard's Star (+44░ 3561) Ophiuchus
5.91
M5
Wolf 359 Leo
7.57
M8
Lalande 21185 (BD+366░ 2147) Ursa Major
8.04
M2
Sirius A Canis Major
8.65
Al
          B Canis Major
8.65
A
Luyten 726-8 A and B Cetus
8.94
M6
Ross 154 Sagittarius
9.45
M5
Ross 248 Andromeda
10.29
M6
e Eridani Eridanus
10.69
K2
Luyten 789-6 Aquarius
10.80
M6
Ross 128 Virgo
10.95
M5
61 Cygni A Cygnus
11.17
K5
               B Cygnus
11.17
K7
e Indi Indus
11.21
KS
Procyon A Canis Minor
11.36
F5
              B Canis Minor
11.36
F
+599░ 1915 A Draco
11.48
M4
S 2398 . B Draco
11.48
M5
Groombridge 34 A (BD+433░ 44) Andromeda
11.57
M2
                          B Andromeda
11.57
M4
Lac 9352 (CD-366░ 15693) Grus
11.69
M2
t Ceti Cetus
11.95
G8
LET 118 (L725-32) Cetus
12.50
M5
Lac 8760 (CD-399░ 14192) Microscopium
12.54
M1
Luyten’s Star (BD+55░ 1668) Canis Minor
12.64
M4
Kapteyn’s Star (-455░ 1841) Pictor
12.74
M0
KrŘger 60 A Cepheus
12.84
M4
                 B Cepheus
12.84
M6
Ross 614 A Monoceros
13.10
M5
                B Monoceros
13.10
M
BD-122░ 4523 Ophiuchus
13.10
M5
Von Maanen's Star (Wolf 28) Pisces
13.94
G
Wolf 424 A and B Virgo
14.24
M6
G 158-27 Cetus
14.43
14
CD-377░ 15492 Sculptor
14.50
M3
Groombridge 1618 (BD+500░ 1725) Ursa Major
15.03
K7
CD-466░ 11540 Ara
15.10
M4
CD-499░ 13515 Grus
15.24
M3
CD-444░ 11909 Scorpius
15.31
M5
Luyten 1159-16 Aries
15.38
M8
BD+688░ 946 Draco
15.76
M3.5
Luyten 145-141 Musca
15.83
A
Ross 780 (BD-155░ 6290) Aquarius
15.83
M5
40 Eridani A Eridanus
15.76
K0
                 B Eridanus
15.76
A
                 C Eridanus
15.76
M4
BD+200░ 2465 Leo
16.15
M4
Altair Aquila
16.64
A7
70 Ophiuchi A Ophiuchus
16.73
K1
                    B Ophiuchus
16.73
K6
AC+799░ 3883 Camelopardalis
16.81
M4
BD+433░ 4305 Lacerta
16.90
M5
Stein 2051 A (AC+58) Camelopardalis
16.99
M5
                  B Camelopardalis
16.99
A
Lalande 25372 (BD+155░ 2620) Bo÷tes
17.40
M2
WX UMa A (+444░ 2051) Ursa Major
17.54
M2
                 B Ursa Major
17.54
M8
36 Ophiuchi A (-266░ 12026) Ophiuchus
17.73
K2
                    B Ophiuchus
17.73
K1
                   C Ophiuchus
17.73
K6
HR 7703 A (-366░ 13940) Sagittarius
18.43
K3
               B Sagittarius
18.43
M5
o Draconis Draco
18.53
K0
Ross 882 (YZ CMi) Canis Minor
18.53
M4
d Pavonis Pavo
18.64
G6
+11░ 4774 Pisces
18.64
M2
Luyten 347-14 Sagittarius
18.64
M7
-211░ 1377 Lepus
18.74
M1
Luyten 97-12 Volans
18.85
F
Luyten 674-15 Puppis
19.07
M
h Cassiopeiae A Cassiopeia
19.19
G0
                       B Cassiopeia
19.19
M0
Luyten 205-128 (UC 48) Ara
19.19
M
HD 36395 (-33░ 1123) Orion
19.19
M1
-400░ 9712 Lupus
19.30
M4
Ross 986 (AC+38) Auriga
19.30
M5
Ross 47 (AC+12) Orion
19.41
M6
Wolf 294 (AC+33) Gemini
19.41
M4
LP 658-2 Orion
19.65
K
+533░ 1320 A and B Ursa Major
19.65
M0
+44░ 4048 A Aquila
19.65
M4
                  B Aquila
19.65
M5
-455░ 13677 Sagittarius
19.89
M0


 

Table 23.4 includes a listing of all "good suns"* within 100 light-years (30 parsecs) of Sol.

 


Table 23.4 Inventory of Good Suns* (F5-K2) within 100 Light-Years of Sol
(selected from Hofflied575)
Star Name
Range
Spectral Class
Star Name
Range
Spectral 
Class
Star Name
Range
Spectral Class
 
(lt-yrs)
   
(lt-yrs)
   
(lt-yrs)
 
a Centauri
4.4
G2
HD196761 (Capricorn)
50
G8
Mu Cygni
72
F6
Epsilon Eridani
10.7
K2
n Phoenicis
51
F8
Theta Antliae
72
F1
Procyon
11.4
F5
111 Tauri
51
F8
HD131923 (Lupus)
72
G7
t Ceti
12.0
G8
Iota Piscium
51
F7
HD53705 (Puppis)
74
G3
40 Omicron Eridani
15.8
K0
26 Draconis
51
G1
HD128020 (Circinus)
74
F5
70 Ophiuchi
16.7
K1
g Cor. Austrinae
51
F8
22 Lyncis
74
F6
36 Ophiuchi
17.7
K1
e Coronae Borealis
52
G2
HD3158 (Phoenix)
76
F6
s Draconis
18.5
K0
KD5015 (Cassiopeia)
53
F8
HD91324 (Vela)
76
F6
d Pavonis
18.6
G6
Upsilon Andromedae
53
F8
HD159964 (Apus)
76
F8
e Cassiopeiae
19.2
G0
81 Cancri
53
K0
66 Ceti
76
F9
82 Eridani
20.2
G5
Chi Cancri
53
F6
Mu Draconis
76
F6
HD10360 (Eridanus)
22
K0
HD122742 (Bo÷tes)
53
G8
16 Ursa Majoris
76
F9
Xi Bo÷tis
22
G8
HD126053 (Virgo)
53
G3
9 Ceti
78
G2
Mu Cassiopeiae
24
G5
45 Bo÷tis
53
F5
75 Cancri
78
G3
Zeta Tucanae
24
G2
6 Ceti
54
F6
68 Eridani
78
F5
107 Piscium
24.3
K1
15 Sagittae
54
G1
Rho Coronae Borealis
78
G2
HD17925 (Eridanus)
26
K0
HD24953 (Grus)
54
G1
HD88218 (Antlia)
78
F9
Xi Ursa Majoris
26
G0
n Lupus
55
G2
Kappa Tucanae
78
F6
HD156274 (Ara)
26
G8
y Ceti
55
F8
HD96700 (Hydra)
78
G2
Pi Orionis
26
F6
HD178428 (Sagitta)
55
G4
HD108799 (Corvus)
78
F8
g Lepus
27
F6
HD30003 (Dorado)
55
G5
HD189245 (Sagittarius
78
F8
Chi Draconis
27
F7
HD34721 (Lepus)
55
G0
HD181655 (Lyra)
73
G8
b Comae Berenices
27.2
G0
HD65907 (Carina)
55
G2
y Pavonis
80
F8
HD1923]0 (Capricorn)
28
K0
18 Scorpii
55
G1
HD81809 (Hydra)
80
G2
61 Virginis
28
G6
HD89744 (Ursa Major)
55
F6
70 Tauri
80
F5
a Mensae
28.3
G5
13 Ceti
56
F8
HD50223 (Puppis)
80
F5
g Pavonis
29
F8
99 Herculis
56
F7
HD179958 (Cygnus)
80
G4
HD10780 (Cassiopeia)
29
K0
104 Tauri
56
G4
70 Virginis
80
G5
61 Ursa Majoris
30
08
HD102438 (Hydra)
56
G5
HD221356 (Aquarius)
80
G0
b Canum Venaticorum
30
G0
HD73752 (Pyxis)
56
G5
HD198084 (Cepheus)
80
F8
Kappa Ceti
31
G5
HD182488 (Lyra)
57
K0
12 Persei
82
F9
Chi Orionis
32
G0
a Comae Berenices
57
F5
HD91889 (Hydra)
82
F8
HD166620 (Hercules)
33
K2
HD63077 (Puppis)
57
G0
HD210918 (Grus)
82
G5
54 Piscium
33
K0
HD120690 (Hydra)
58
G5
HD123 (Cassiopeia)
84
04
HD100623 (Hydra)
33
K0
t Bo÷tis
58
F7
HD45588 (Canis Major)
84
F9
b Virginia
33
F8
HD176051 (Lyra)
58
G0
Zeta Cancri
84
F8
Zeta Reticuli A
34
G2
Chi Herculis
58
F9
Omega Draconis
84
F5
Zeta Reticuli B
34
G1
H042807 (Orion)
58
G6
HD111456 (Ursa Major)
84
F6
HD14412 (Fornax)
35
G5
HD48938 (Canis Major)
58
F8
HD184985 (Sagittarius)
84
F6
HD102365 (Centaurus)
35
G5
Omega Sagittarii
59
G5
38 Leonis Minoris
86
F8
HD37394 (Auriga)
36
K2
10 Tauri
60
F8
HD223731 (Cepheus)
86
F5
l Serpentis
36
G0
HD73524 (Vela)
60
G1
89 Leonis
86
F5
d Trianguli
36
G0
58 Ophiuchi
60
F5
HD99453 (Centaurus)
86
F8
Psi Capricorni
36
F5
53 Aquarii
60
G2
19 Leonis Minoris
86
F5
12 Ophiuchi
37
K0
20 Leonis Minoris
62
G4
34 Pegasi
86
F5
HD10307 (Andromeda)
38
G2
83 Leonis
62
K0
Xi Capricorni
86
F8
85 Pegasi
38
G3
g Doradus
62
F5
38 Cassiopeiae
88
F6
Iota Persei
39
G0
HD33564 (Camelopardus)
62
F6
HD12042 (Eridanus)
88
F7
HD131511 (Bo÷tes)
39
K1
HD197076 (Deiphinus)
62
G2
71 Orionis
88
F6
HD13445 (Eridanus)
39
K0
d Equulei
62
F7
HD44120 (Pictor)
88
G0
Zeta Trianguli Australis
39
G0
HD25457 (Eridanus)
62
F6
HD55575 (Lynx)
88
G0
HD72673 (Pyxis)
41
K0
HD3823 (Tucana)
63
G1
HD189340 (Aquila)
88
G0
36 Ursa Majoris
41
F8
Kappa Reticuli
63
F5
7 Canum Venaticorum
88
F6
Zeta Doradus
42
F8
HD212330 (Tucana)
63
G4
HD3795 (Cetus)
91
G3
HD76151 (Hydra)
42
G3
HD68456 (Carina)
64
F7
38 Virginis
91
F6
HD104304 (Virgo)
42
G7
b Caeli
64
F8
HD2O3454 (Cygnus)
91
F8
Theta Persei
42
F7
HD80671 (Carina)
64
F5
HD11007 (Triangulum)
91
F6
HD211415 (Grus)
42
G1
HD90508 (Ursa Major)
64
G1
HD14214 (Cetus)
91
F9
44 Bo÷tis
43
G1
HD159222 (Hercules)
64
G5
HD219623 (Andromeda)
91
F7
HD158633 (Draco)
43
K1
HD119124 (Ursa Major)
65
F9
11 Aquarius
91
G1
59 Virginis
43
F8
HD2O4121 (Aquarius)
65
F5
HD122862 (Apus)
93
G1
HD69830 (Puppis)
43
G8
l Fornacis
67
G1
HD184960 (Cygnus)
93
F8
Rho Cancri
44
K0
94 Ceti
67
F8
39 Serpentis
93
G2
Iota Pegasi
44
F5
HD88742 (Antliae)
67
G1
112 Piscium
93
G1
47 Ursa Majoris
45
G0
HD147513 (Scorpius)
67
G5
HD175225 (Draco)
93
G8
51 Pegasi
45
G5
110 Herculis
67
F6
Rho Arietis
93
F5
HD84117 (Hydra)
45
G0
HD2O2940 (Capricorn)
67
G5
HD2O0375 (Aquarius)
93
F5
HD130948 (Bodtes)
46
G2
HD43587 (Orion)
68
G0
HD28255 (Dorado)
93
G0
Mu Arae
46
G5
HD72945 (Hydra)
68
F6
HD41700 (Puppis)
93
F8
HD3443 (Cetus)
47
G5
HD100203 (Ursa Major)
68
F6
HD225239 (Andromeda)
96
G2
Kappa Fornacis
47
G1
g Coronae Austrinae
68
F8
16 Cygni
96
02
HD166 (Pegasus)
47
K0
Xi Pegasi
69
F7
HD43318 (Orion)
96
F6
19 Draconis
47
F6
HD189567 (Pavo)
69
G2
64 Ceti
96
F8
39 Tauri
47
G1
36 Draconis
69
F5
HD44594 (Puppis)
96
G0
HD140901 (Lupus)
47
G6
17 Cygni
69
F5
HD201647 (Microscopium)
96
F7
HD62613 (Camelopardus)
47
G8
HD114613 (Centaurus)
69
G3
HD218630 (Gras)
96
F6
72 Herculis
47
G2
HD114837 (Centaurus)
69
F8
HD2475 (Cetus)
96
G0
HD76943 (Lynx)
47
F5
s Coronae Borealis
69
F6
18 Puppis
96
F7
HD207129 (Grus)
48
G2
64 Piscium
71
F8
     
Psi Aurigae
48
G0
HD168009 (Vega)
71
G0
     
t Hydrae
49
F6
t Piscis Austrini
71
F5
     
HD206860 (Pegasus)
49
G0
Iota Pavonis
71
G0
     
t Eridanj
49
F6
50 Persei
71
F7
     
Theta Bo÷tis
49
F7
HD41330 (Auriga)
71
G0
   
.
HD39881 (Orion)
49
G0
HD1544]7 (Ophiuchus)
71
F8
     
HD64379 (Puppis)
49
F5
HD46588 (Camelopardus)
71
F6
     
58 Eridani
49
G1
HD71148 (Lynx) 
71
G4
.
   
l Aurigae
49
G0
HD213429 (Aquarius)
71
F8
     
HD84737 (Ursa Major)
49
G1
HD94388 (Crater)
71
F6
     
HD193664 (Draco)
49
GS
Psi Serpentis
71
G5
     
HD224636 (Andromeda)
50
G0
HD136064 (Ursa Minor)
71
F8
     
HD224635 (Andromeda)
50
G0
HD103437 (Centaurus)
71
F8
     
Puppis 
50
G1
Omicron Aquilae
71
F8
     
Pi Ursa Majoris
50
G0
HD186760 (Cygnus)
72
F8
     
Canum Venaticorum
50
G0
HD49095 (Canis Major)
72
F6
     

*In this context, a "good sun" is a Main Sequence dwarf (Sol-like) belonging to stellar classes F5-K2. The nearest to Sol is the  a Centauri star system,3089 which recently has been discovered to be 6 eons old and significantly richer in heavy elements than our own solar system.3224


 

Due to unavoidably deficient data, Table 23.4 is complete only out to about 40 light-years. From 40-100 light-years, data are available only for about 25% of the "good suns" expected to lie at this range. The deficiency is almost exclusively among the class K stars (which are harder to measure at great distances) beyond 40 light-years, although many late class G suns are also missing beyond 50-60 light-years.

 


Last updated on 6 December 2008