We present an analysis of our extensive data-set on IRAS 08544-4431 .
It is the first object we discuss of our newly defined sample of stars , selected for their position in the ‘ RV Tauri ’ box in the IRAS [ 12 ] - [ 25 ] , [ 25 ] - [ 60 ] two-color diagram .
Moreover , our selection criteria included an observed excess in the L-band , indicative of a dusty disc .
The SED of IRAS 08544-4431 shows a broad IR excess starting already at H .
Our optical photometric data reveal some evidence for deep and shallow minima in the light curve and a pulsation time-scale of around 100 days with a small amplitude ( \Delta V peak-to-peak = 0.17 mag ) .
Our CORALIE radial velocity measurements show that IRAS 08544-4431 is a binary system with a period of 499 \pm 3 days and a mass function of 0.02 M _ { \odot } .
Moreover , IRAS 08544-4431 is detected in both the CO ( 2-1 ) and ( 1-0 ) mm-wave emission lines .
The triangular shape of the weak CO profile confirms that part of the circumstellar material is not freely expanding but resides probably in a dusty circumbinary disc .
Our chemical abundance analysis of a high resolution spectrum of high S/N reveals that a depletion process has modified the photospheric abundances to a moderate extent ( [ Zn/Fe ] =+0.4 ) .
All these findings confirm that the F-type IRAS 08544-4431 is another good example of a binary Post-AGB star surrounded by a dusty disc .
The H \alpha 
P-Cygni profile shows ongoing mass-loss with a very high outflow velocity , the origin of which is not understood .
The strength and velocity of the H \alpha -absorption are modulated with the orbital motion ; the maxima of both quantities ( \sim 400 \kms , 5 Å respectively ) occur at superior conjunction .