Stellar Luminsoity Classes

Class	Description	Typical Luminosity  (solar luminosities)
Ia	Bright supergiants	500,000
Iab	Moderate supergiants	125,000
Ib	Supergiants	8,000
II	Bright giants	1,300
III	Giants	100
IV	Subgiants	25
V	Main-sequence stars/dwarfs	Entire range of values

White Dwarfs are not included in this system, but are usually denoted by a "D" - for example, DA indicates a white dwarf of spectral type A.