Quantitative stellar spectral classification

Equivalent widths of 19 absorption lines in CCD slit spectra of 487 stars a re compared with their respective (B - V) colors, their absolute magnitudes derived from Hipparcos parallaxes, and with their metallicity indices. Alg orithms are found which yield the absolute magnitudes for all spectral type s with an average error of 0.26 magnitudes. The (B - V) colors can be repro duced with an average error of 0.018 magnitudes for early type stars, and w ith an average error of 0.020 magnitudes Cor late type stars. The metallici ty is recovered with an average error of 0.06 for early type stars, and an average error of 0.07 for late type stars.