THE CHEMICAL-COMPOSITION OF IRAS-05341- A POST-AGB F SUPERGIANT WITH 21 MU-M EMISSION(0852 )

An abundance analysis of the photosphere of the F-type Post-AGE candid ate IRAS 05341 + 0852 is presented. The analysis of the spectra sugges ts that the atmospheric model: T-eff = 6500 K, log g = 0.5, xi(t) = 5 km s(-1) and [M/H] = 1.0, best represents the photosphere of the star. We find that the star is metal-poor ([Fe/H] = -0.9) and carbon-rich ( C/O approximate to 1.9). Lithium, carbon, nitrogen, oxygen, aluminum a nd silicon are found to be overabundant. Most importantly this star ha s large overabundance of s-process elements which are as follows: [Y/F e] = 1.6, [Ba/Fe] = 2.2, [La/Fe] = 2.9, [Ce/Fe] = 1.6, [Pr/Fe] = 1.8, [Nd/Fe] = 2.0, and [Sm/Fe] = 1.7. These s-process enhancements are of similar magnitude to those seen in FG Sge. The enhancement of Li and A l are expected due to Hot Bottom Burning (HBE), in massive AGE stars. However, the low metallicity, heliocentric radial velocity (v(r) = 25 km s(-1)), and the high Galactic latitude (b = -12 degrees) suggest th at IRAS 05341 + 0852 is a low-mass star. Also the [S/Fe] = 0.2 indicat es that the low Fe abundance is intrinsic and is not due to fractionat ion. The significant overabundance of lithium (log epsilon less than o r equal to 2.5) and aluminum ([Al/Fe] = 1.4) in this star is a puzzle. Furthermore we have detected the C-2 Phillips and CN Red bands in abs orption. We find rotational temperatures, column densities, and expans ion velocities which show that these lines are formed in the detached circumstellar dust shell (the AGE ejecta) and we find an expansion vel ocity of the AGE ejecta of V-exp = 10.8 +/- 1.0 km s(-1).