ocr: SPECTRAL CLASS Stars are divided into classes according to the lines they display in their spec- trums. According to the currently used Harvard classitication, stars are divided into seven main types, which are further divided into subtypes 0 to 9. The main types are 0.,B,A.E,G.,K-ond M. Spectral class Colour of the star Surface temperaturer") Example star Blue 20.000-35,000 Alnitak B star Bluish 01.000-25,000 Rigel A star White 7400011,000 Sirius Fstar Yellowish 600007400 Polaris G star Yellow 5,500 Sun Kstar Orange 4,000 Arcturus Mstar Red 3000 Betelgeuze Inc addition to the aforemenfioned, ...
