The Classification of Stars

This diagram shows most of the major types of stars. The vast majority of stars are main sequence stars - these are star like the Sun that are burning hydrogen into helium to produce their energy. Most stars spend 90% of their life as main sequence stars. When stars exhaust their hydrogen fuel the outer layers of the star can expand greatly and the star becomes a giant. This only lasts a few million years before the star throws off its outer layers revealing a degenerate core, or in extreme cases a black hole.

This diagram shows typical average properties for the different types of stars. There is also a negative version of this diagram which might be easier to print.

Stellar classification

Detailed Stellar Properties

Main Sequence Stars (V)

TypeSurface
Temp.
Radius
(Sun=1)
Mass
(Sun=1)
Absolute
Magnitude
(Visual)
Luminosity
(bolometric)
(Sun=1)
Habitable Zone
(AU)
Lifetime
(million y)
Abundance
(% of all stars)
O3 53 000K 15 120 -6.01 400 0001200 2 0.00001%
O5 45 000K 12 60 -5.7 790 000 890 3
O8 35 000K 8.5 23 -4.9 170 000 410 6
B0 30 000K 7.4 17 -4.0 50 000220 9 0.1%
B3 19 000K 4.8 7.6 -1.6 1900 44 30
B5 15 000K 3.9 5.9 -1.2 830 29 50
B8 12 000K 3.0 3.8 -0.2 180 13 150
A0 9 500K 2.4 2.9 +0.6 54 7.3 300 0.7%
A5 8 200K 1.7 2.0 +1.9 14 3.7 1 000
F07 200K1.51.6+2.7 6.52.5 1 900 2%
F56 400K1.31.3+3.5 3.21.8 3 200
G0 6 000K 1.1 1.05+4.4 1.5 1.2 8 000 3.5%
G2 5 800K 1.0 1.00+4.8 1.0 1.0 10 000
G5 5 700K 0.920.92+5.1 0.790.8912 000
K0 5 200K 0.850.79+5.9 0.420.6522 000 8%
K5 4 300K 0.720.67+7.4 0.150.3945 000
M0 3 800K 0.60 0.51 +8.8 0.08 0.28 68 000 80%
M5 3 200K 0.27 0.21 +12.3 0.011 0.10 200 000
M8 2 600K 0.15 0.06 +16.0 0.001 0.03 700 000

Giant Stars (III)

TypeSurface
Temp.
Radius
(Sun=1)
Mass
(Sun=1)
Absolute
Magnitude
(Visual)
Luminosity
(bolometric)
(Sun=1)
Habitable Zone
(AU)
B0 29 000K 15 20 -5.11 100 0001000
B5 15 000K 8 7 -2.21800 42
A0 10 000K 5 4 +0.0 110 11
F07 200K 5 2+0.560 7.7
G0 5 800K 6 1.0 +1.0 34 5.8
G5 5 100K 10 1.1 +0.9 43 6.6
K0 4 700K 15 1.1 +0.7 60 7.7
K5 3 900K 25 1.2 -0.2220 15
M0 3 800K 40 1.2 -0.4 330 18
M5 3 300K 80 1.2 -0.3 930 30

Supergiant Stars (I)

TypeSurface
Temp.
Radius
(Sun=1)
Mass
(Sun=1)
Absolute
Magnitude
(Visual)
Luminosity
(bolometric)
(Sun=1)
Habitable Zone
(AU)
O5 40 000K 30 70 -6.611 000 000 3300
B0 26 000K 30 25 -6.42 600 0001600
A0 9 700K 60 16 -6.3 35 000 190
F07 700K8012-6.632 000 180
G0 5 500K120 10 -6.4 30 000 170
G5 4 800K150 12 -6.2 29 000 170
K0 4 400K200 13 -6.0 29 000 170
K5 3 800K400 13 -5.8 38 000 190
M0 3 600K 500 13 -5.6 41 000 200

Brown Dwarfs

TypeSurface
Temp.
Radius
(Sun=1)
Absolute
Magnitude
(Visual)
Luminosity
(bolometric)
(Sun=1)
Habitable Zone
(AU)
Habitable Zone
(km)
M8 2 600K 0.11 +18.5 0.00045 0.021 3 100 000
M9 2 500K 0.10 +19.3 0.00032 0.018 2 700 000
L0 2 400K 0.098+19.7 0.00030 0.017 2 500 000
L2 2 100K 0.095+20.4 0.00015 0.012 1 800 000
L5 1 650K 0.089+22 0.000060 0.00781 200 000
T01 400K0.08+23 0.000028 0.0052 780 000
T51 200K0.06+24 0.000015 0.0039 580 000
T8 750K0.06+26 0.00000260.0016 240 000

The solar neighborhood Back to the Solar Neighbourhood page