Determining the physical properties of the B stars. II. Calibration of synthetic photometry

We present a new calibration of optical (UBV, Stromgren u nu by beta, and Geneva) and near-IR (Johnson RIJHK and Two Micron All Sky Survey) photometry for B and early A stars derived from Kurucz ATLAS9 model atmospheres. sphres. Our sample of stars consists of 45 normal nearby B and early A stars that have high-quality, low-resolution IUE spectra and accurate Hipparcos parallaxes. The calibration is unique because it relies only on the UV spectral energy distributions, the absolute flux calibration of the V filter, and the Hipparcos distances to determine the appropriate model atmospheres for the program stars. These models are then used to calibrate the synthetic photometry. We compare our results with previous well-accepted results and provide a thorough discussion of the random errors and systematic effects affecting the calibration. In particular, we demonstrate the influence of nu sin i on surface gravities derived from fitting model atmospheres. Finally, we discuss some of our intended applications of this new calibration.