Definition Stars are classified based on the ionization state of their atmosphere and thus on their surface temperature. From hottest to coolest, the classification goes as O, B, A, F, G, K, and M (with the mnemonic "Oh Be A Fine Girl/Guy, Kiss Me"): Each category has ten ...
The stars are divided into 7 classes designated by the letters O, B, A, F, G, K, and M; the hottest stars (O and B) are blue-white in color, while the coolest (M) are red. Each of the letter classes has subdivisions indicated by numerals 0 through 9. Thus, a B0 is the ...
Blue Giant Starshave spectral types O, B, A. O is a deep blue, B is more white and As is very light, bordering on white. Blue stars are the hottest stars in the universe. Red stars, immaterial of size, are the coolest stars in the universe. Onlybrown starsare cooler. Brown stars...
Star - Spectral Types, Classification, Astronomy: Most stars are grouped into a small number of spectral types. The Henry Draper Catalogue and the Bright Star Catalogue list spectral types from the hottest to the coolest stars (see stellar classification