A Li-rich post-AGB star HD 172481

Abstract

Our abundance analysis of this post-AGB candidate star confirms that the HD 172481 is indeed a post-AGB star. It belongs to an important, but relatively rare class of post-AGB stars showing Li I features in their spectra. The strength of OI triplet at 7774 Å confirms its high luminosity (log, (L/L?) ~ 4). It is moderately metal-poor with [Fe/H] of - 0.6 but shows significant enrichment of s-process elements indicating that the star has gone through the third dredge-up. We find C/O of ~ 0.4 for this star. Hot Bottom Burning scenario can explain the production of Li as well as the destruction of carbon via CN cycle that could prevent C/O ratio from exceeding one.