Star Spectral Classifications


Class 

Spectrum 

Color 

Temperature (K)

 

O

Ionized and neutral helium; weakened hydrogen

bluish

31,500 49,000


B

Neutral helium, stronger hydrogen

blue-white

10,000 31,500


A

Strong hydrogen, ionized metals

white

7,500 -10,000


F

Weaker hydrogen, ionized metals

yellowish-white

6,000 7,500


G

Still weaker hydrogen, ionized and neutralized metals

yellowish

5,300 6,000


K

Weak hydrogen, neutral metals

orange

3,800 5,300


M

Little or no hydrogen, neutral metals, molecules

reddish

2,100 3,800


L

No hydrogen, metallic hybrids, alkalai metals

red-infrared

1,200 2,100


T

Methane bands

infrared

Under 1,200