Spectral Classifications

Spectral Classifications
Type	Color	Major Spectral Features	Temperature	Examples
O	Blue-Violet	H, He II	30000	δ Orionis
B	Blue-White	Stronger H, He I	20000	Spica, Rigel
A	White	H at maximum strength, Weak Ca II	7500-11000	Vega, Sirius
F	Yellow-White	H weaker, Ionized metals, Ca II stronger	6000-7500	Procyon
G	Yellow	H still weaker, Ca II strongest, neutral metals	5000-6000	Sun, Capella
K	Orange	H even weaker, Ca II strong, but weaker; weak molecular bands	3500-5000	Arcturus, Aldebaran
M	Red-Orange	H lines very weak but present, strong molecular bands, especially TiO	2800-3500	Antares, Betelguese
L	Red	Molecular Bands, Most Radiation in Infrared	1400-2800	No Naked-Eye Examples
T	Deep Red	Molecular Bands, Most Radiation in Infrared	800-1400	No Naked-Eye Examples

Helpful Mneumonic: Oh Be A Fine Girl, Kiss Me! Lovingly, Tenderly!