SIMBAD references

A new empirical brightness calibration of early-type stars is presented, entirely based on accurate binary data. This calibration agrees remarkably well with the predictions of the most recent stellar models, but disagrees completely with all other currently used calibrations for early-type stars. The binaries used to derive the new calibration cover a range of masses from about 1.3M_☉ to 25M_☉, corresponding to a temperature range from 6700K to 38000K. Over the whole mass range, no systematic differences between the observed and evolutionary masses were found. The application to the α Per cluster gives a distance modulus which agrees perfectly with that derived by comparing its lower main-sequence to stars with known parallaxes.