The circumstellar dust of MU Cephei

An accurate solution to the equation of transfer in spherical geometry (including an anisotropic phase function) is used to model IUE observations of the circumstellar extinction of Mu Cep. Some grain materials can thus be eliminated from consideration while others can be restricted in grain size (and envelope optical depth). Further discrimination of candidate grain models is achieved through analysis of the thermal infrared emission. It is found that circumstellar dust similar to basaltic glass with enhanced near-infrared absorptivity would satisfy observations in both wavelength regimes.