THE PRECISION OF SPECTROSCOPIC LUMINOSITY IN A-F TYPE STARS AND THE CLASSIFICATION OF AM STARS

We analyze the work of three teams of classifiers providing spectral c lassifications in the range of late B-type to early F-type stars. With the help of a statistical model we derive an accuracy of +/- O.7 lumi nosity classes for the spectroscopic luminosity class provided by clas sifiers. This is sligthly better than one luminosity class, and corres ponds, in the region of the A-type stars, to a precision of about +/- 0.4 (absolute) magnitudes. We do not find differences in the precision of three series analyzed. We analyze also the case of Am stars and co nclude that the probability that two independent classifiers agree tha t a given object is Am, is of the order of 60%.