51 Tauri and the Hyades distance modulus

Major additions are made here to the analysis of the distance modulus for the Hyades of 3.36 + or - 0.05 mag derived previously by the authors. It is noted that 51 Tau, a system resolved by speckle interferometry and a single-lined spectroscopic binary, can replace vB 22 in the earlier analysis. The resulting distance modulus is identical with that obtained previously. Second, it is noted that 51 Tau and vB 22 can be combined with the visual binaries to provide both a better estimate of the distance modulus and an independent estimate of the exponent of the mass-luminosity relation, a quantity which previously had to be assumed in the analysis. Realistic estimates of the uncertainties of the masses derived from the visual binaries ar obtained by reconsidering the orbits of these systems. Using a generalized last-squares procedure, almost no change is found the the previous estimate of the distance modulus, but a dramatically reduced uncertainty is obtained.