ON THE EFFECTIVE TEMPERATURES, SURFACE GRAVITIES, AND OPTICAL-REGION FLUXES OF THE MAGNETIC CP STARS

We determined effective temperatures and surface gravities for five MC P stars using ATLAS9 metal-rich model atmospheres, optical region spec trophotometry, and H gamma profiles. The predictions of these models f it the continua significantly better than do those of previous generat ion ATLAS models. They can even match the 5200 Angstrom broad, continu um features in three stars where this feature is of moderate strength. A synthesized spectrum of one of these stars, HD 43819, suggests that this feature is at least due partially to differential line blanketin g. However, problems remain in fitting the optical region energy distr ibutions of stars with stronger 5200 Angstrom features. The 4200 Angst rom and the 6300 Angstrom features are not reproduced in the models. T he relationship between the strength of the 5200 Angstrom feature and metallicity was also explored using spectrophotometric and photometric indices.