Spectral class
Encyclopedia : S : SP : SPE : Spectral class
In astronomy one method of classifying stars is through the analysis of their absorption spectra, by this method stars are assigned a spectral class. Since the absorption spectra is dependent on the surface temperature of the star the spectral class gives an indications of the temperature of the star.
The current system of naming spectral class was adopted in 1910 and consists of a letter and a number from 0 to 9, for example the spectral class of the sun is G2. The letters used are in decreasing order of temperature
O B A F G K M
The number is used to sub-divide these with the lower the number the higher the temperature so a star classed as F4 would be hotter than a star classed as F9.
See also
From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.