"Oh Be A Fine Girl Kiss Me" and the Types of Stars.

After a series of observations of many years, astronomers ranked the Stars in 7 groups (O - B - A - F - G - K - M) according to the type of spectrum of each Star. For each spectrum type class there are 10 subdivisions denoted by numbers from 0 to 9.
The easiest way to remember all 7 types of spectrum, in the correct order that they are sorted, is "Oh Be A Fine Girl Kiss Me," where all the original matches correspond to each star type.
The Spectrum Types are as follows:
"O" = cyan color with a surface temperature above 25,000K "B" = cyan-white color with a surface temperature of 10,000K to 25,000K "A" = white color with a surface temperature of 7500K to 10,000K "F" = yellow color with a surface temperature of 6000K to 7500K "G" = yellow-orange color with a surface temperature of 5000K to 6000K "K" = orange color with a surface temperature of 3500K to 5000K "M" = red color with a surface temperature below 3500K
The next time you see a well-known star and / or constellation, for example Scorpio, whisper "Oh Be A Fine Girl Kiss Me" and then you will easily understand that Antares belongs to the M ".
* Our Sun is a medium star "G". * The H-R (Hertzsprung-Russell) diagram depicts the most famous stars of our galaxy.
Andreas Panayiotou
Cyprus Astronomy Organisation