THE CHEMICAL-COMPOSITION OF THE RV TAURI VARIABLE IW CARINAE

Analysis of the RV Tauri star IW Carinae shows a photospheric composit ion unlike that reported previously for a few other RV Tau stars but r esembling that of certain post-AGE stars. IW Car is carbon-rich: sever al lines of C I are detected and suggest C/O greater than or equal to 1. The star is generally metal poor. The composition of [Fe/H] similar to - 1.0, [Ca/H] similar to -1.9 but [Zn/H] similar to 0.0 reflects t hat of gas of solar metallicity from which easily condensable elements have condensed into dust grains and been removed from the star's phot osphere. Separation of gas and dust may have occurred in the present o r recent stellar wind of IW Car. These characteristics also suggest th at RV Tauri stars are post-AGE objects.