We present a study of low- and high-resolution ultraviolet , high-resolution optical CAT/CES spectra and ultraviolet , optical and infrared photometry of the peculiar supergiant HD 101584 .
From the photometry we learn that the ultraviolet and optical energy distribution can not be fitted in a consistent way and we need a model in which the UV and optical energy distribution are formed by different gas .
The Geneva photometry is best fitted to a B9II Kurucz model , T _ { eff } = 12000 \pm 1000 K and \log g = 3.0 \pm 1.0 , with an extinction of E ( B - V ) = 0.49 \pm 0.05 .

The observed spectral features in the spectrum of HD 101584 are classified in eight different categories based on the velocity , shape of profile and the identification .
The high-excitation HeI ( \chi = 20.87 eV ) , NII ( \chi = 18.40 eV ) , CII ( \chi = 14.39 eV ) and NI ( \chi = 10.29 eV ) optical absorption lines are formed in the photosphere of a late B-star ( e.g .
B8-9I-II ) .
These absorption lines show radial velocity variations which are attributed to binary motion , with the secondary being a white dwarf or a low-mass main sequence object .
The low-excitation P-Cygni lines in the optical and UV are formed in the wind .
The number density of absorption lines in the UV is so large that the wind spectrum acts as an iron curtain in front of the B-star .
The terminal velocity of the wind of v _ { \infty } = 100 \pm 30 km s ^ { -1 } ~ { } is consistent with the star being a low-mass post-AGB star and the low effective gravity is attributed to the presence of a nearby , unseen , secondary .
We estimate a mass-loss rate of Ṁ \approx 10 ^ { -8 } M _ { \odot } yr ^ { -1 } .
Narrow absorption and emission lines are observed which are formed in a circumsystem disk with a typical radius of 10 ^ { 2 } R _ { \ast } .