2008AJ....136.1388T

Using a protocol developed in previous papers in this series, the character of the Pleiades reddening is investigated. The protocol includes (1) analyses that yield results at the few-millimag level of precision and accuracy, (2) derivation of rigorous foundations for reddening values, (3) use of reddening techniques with limited metallicity sensitivity, (4) explicit zero-point control of input data, and (5) use of statistical analysis. It is found that in the eastern part of the Pleiades (as defined in a paper by Breger), E(B - V) = 34±11 mmag, with the quoted standard error depicting the amount of nonuniform reddening. In the western part of the Pleiades outside the "Southwest Nebula" (where E(B - V)>0.2 mag), the mean value of E(B - V) = 57±5.8 mmag, and the intrinsic rms scatter in E(B - V) is 32 mmag. These results show that a widely adopted model in which E(B - V) = 0.04 mag everywhere in the Pleiades outside the Southwest Nebula is not correct for any extended region in the Pleiades. They also show that the photometric properties of brown dwarfs in the western part of the Pleiades are not yet well established. In a collateral analysis, published high-dispersion values of [Fe/H] are used to derive mean metallicities for the Pleiades and Praesepe. The resulting values of [Fe/H] are -0.039±0.014 dex and +0.057±0.022 dex, respectively. When these results are combined with a mean high-dispersion metallicity for the Hyades, it is found that they are strongly inconsistent with a published explanation for the Pleiades distance modulus problem that is based specifically on photometric metallicities.