Harvard spectral classification. The Harvard system is a one-dimensional classification scheme by astronomer Annie Jump Cannon, who re-ordered and simplified a prior alphabetical system. Stars are grouped according to their spectral characteristics by single letters of the alphabet, optionally with numeric subdivisions A-type main-sequence star - Carbon star - K-type main-sequence star. “Henry Draper Catalogue”, published by astronomers at the Harvard College Observatory. It listed , stars. The classification sequence included 7 categories named with letters: O,B,A,F,G,K,M. The sequence is solely based on the progression of line patterns in the spectra (A. Maury). As an example of the full classification of a star, let us consider the Sun. It is a main sequence star (luminosity class 'V') with a temperature of about 5, Kelvin. In the modern Harvard classification scheme, our Sun is a G2V star.
The bible: „Stellar Spectral Classification“,. R.O. Gray, C. J. Corbally, , Princeton Series in Astrophysics. ○ Older, but a good overview: „The. Classification. Spectral Classification of Stars. Historical Development. The analysis of stellar spectra begins with Joseph von Fraunhofer's observations () of the solar. The atlas is divided into pages for each spectral type, with each page containing a short description of the stellar type, characteristic spectral features, and a brief.
The Classification of Stellar Spectra. In , William Wollaston noted that the spectrum of sunlight did not appear to be a continuous band of colours. Although based on the absorption lines, spectral type tells you about the surface temperature of the star. One can see that there are few spectral lines in the early . What's the most important thing to know about stars? Brightness, yes, but also spectral types — without a spectral type, a star is a meaningless.