Spectral Classes

Notice: Pictures and texts are used with the kind permission of Chris Adamek (sttff.net) for non-commercial purposes. 
Some texts and details were altered to better fit the intended RPG setting.

MAIN SEQUENCE CLASSIFICATION

Stars can generally be classified by their color which is defined by their temperature. A purple star is always Class O, a yellow star is always Class G. However, there can be vast differences within each class. Most Class M stars are tiny and don’t emit much light… however, many K- and G-type stars can evolve into red giants. That makes them Class M (giants), but they are NOTHING like the tiny stars that make up the vast majority of Class M stars. Since most stars spend most of their lives on the Main Sequence, the descriptions on this page can be applied to the majority of stars. The oddballs and outsiders don’t necessarily fit the exact parameters here (and will be discussed elsewhere), but even the oddballs conform to the interstellar color scheme, so even a blue oddball is class B.

SPECTRAL CLASS 0

Color
Surface Temperature
Composition
Mass
Radius
Luminosity
Magnitude
Abundance
Lifetime
Death

dark blue/violet
28,000° – 50,000° K
ionized atoms, helium
60 sols
15 sols
1,400,000
-3
0.00000003125% of all stars
10 million years
supernova, becomes a black hole or neutron star

#9a1fff

SPECTRAL CLASS B

Color
Surface Temperature
Composition
Mass
Radius
Luminosity
Magnitude
Abundance
Lifetime
Death

blue
10,000° – 28,000° K
neutral helium, some hydrogen
60 sols
15 sols
1,400,000
-3
0.00000003125% of all stars
10 million years
supernova, becomes a black hole or neutron star

#1c59c4

SPECTRAL CLASS A

Color
Surface Temperature
Composition
Mass
Radius
Luminosity
Magnitude
Abundance
Lifetime
Death

light blue
10,000° – 28,000° K
strong hydrogen and ionized metals
3.2 sols
2.5 sols
80
+1
0.6% of all stars
1 billion years
becomes a White Dwarf

#6ec1e4

SPECTRAL CLASS F

Color
Surface Temperature
Composition
Mass
Radius
Luminosity
Magnitude
Abundance
Lifetime
Death

white
6,000° – 7,000° K
hydrogen, ionized metals, calcium, iron
1.7 sols
1.3 sols
6
+3
3% of all stars
3 billion years
expands to a red giant, becomes planetary nebula and later, a white dwarf

#ffffff

SPECTRAL CLASS G

Color
Surface Temperature
Composition
Mass
Radius
Luminosity
Magnitude
Abundance
Lifetime
Death

yellow
5,000° – 6,000° K
ionized calcium, neutral and ionized metals
1.1 sols
1.1 sols
1.2
+5
7.6% of all stars
10 billion years
expands to a red giant, becomes planetary nebula and later, a white dwarf

#f6ed00

SPECTRAL CLASS K

Color
Surface Temperature
Composition
Mass
Radius
Luminosity
Magnitude
Abundance
Lifetime
Death

orange
3,500° – 5,000° K
neutral metals
0.7 sols
0.4 sols
0.4
+10
12.1% of all stars
50 billion years
expands to a red giant, becomes a white dwarf

#ff9a19

SPECTRAL CLASS M

Color
Surface Temperature
Composition
Mass
Radius
Luminosity
Magnitude
Abundance
Lifetime
Death

red
2,500° – 3,500° K
ionized atoms, helium
0.2 sols
0.3 sols
0.04
+15
76.45% of all stars
1 trillion years or more
becomes a white dwarf

#ff0000

SPECTRAL CLASS L

Color
Surface Temperature
Composition
Mass
Radius
Luminosity
Magnitude
Abundance
Lifetime
Death

dark red
1,300° – 2,500° K
metal hydride, neutral metals
0.1 sols
0.2 sols
0.02
+20
(possibly very abundant)
1 trillion years or more
becomes a brown dwarf

#8b0000

SPECTRAL CLASS T

Color
Surface Temperature
Composition
Mass
Radius
Luminosity
Magnitude
Abundance
Lifetime
Death

brown
550 – 1,300° K
methane
0.08 sols
0.08 sols
0.001
+25
(possibly very abundant)
1 trillion years or more

#8B4513