Empirical calibrations of the uvby, beta system. III. The A-type stars.

Photoelectric photometric four-color and HP indices have been calibrated for A-type stars (stars with 2.890 > P> 2.720 and c 1 <0.28 that are not B-type stars) in terms of intrinsic color and absolute magnitude by using data for bright stars and stars in several open clusters. Intrinsic color indices should be predictable to about +0.01 mag and absolute magnitude to + 0.3 mag. Systematic effects can exist in the absolute magnitude calibration due to rotational velocity. Am-type stars appear to fit the calibration well. There is quite a good agreement between the photometric classification and MK spectral classification.