  Recent photospheric abundance studies of galactic field RV Tauri stars show
that depletion of refractory elements is rather common in these evolved
objects. The process that creates this chemical anomaly is not understood well,
but it probably requires the presence of gravitationally bound dust in a binary
system. We test for the presence of depletion in extra-galactic objects. A
detailed photospheric abundance study on the basis of high-quality UVES spectra
was performed on the RV Tauri star in the LMC: MACHO82.8405.15. Abundances were
derived using a critically compiled line list with accurate log(gf) values and
the latest Kurucz model atmospheres. With [Fe/H]=-2.6 in combination with
[Zn/Fe]=+2.3 and [S/Ti]=+2.5, MACHO82.8405.15 displays a strong depletion
abundance pattern. The effect of the depletion is comparable to the strongest
depletions seen in field Galactic RV Tauri stars. The chemical analysis of
MACHO82.8405.15 proves that the depletion process also occurs in the
extragalactic members of the RV Tauri pulsation class. Our program star is a
member of a larger sample of LMC RV Tauri objects. This sample is unique, since
the distances of the members are well-constrained. Further studies of this
sample are therefore expected to gain deeper insight into the poorly understood
depletion phenomenon and of the evolutionary status of RV Tauri stars in
general.
