CD -24_17504 revisited: a new comprehensive element abundance analysis

TL;DR

This paper provides a new, detailed high-resolution abundance analysis of the metal-poor star CD -24_17504, updating previous results with improved data and including new measurements of carbon and neutron-capture elements.

Contribution

It offers the most comprehensive and high-quality element abundance analysis of CD -24_17504 to date, with new measurements of carbon and neutron-capture element limits.

Findings

Star has [Fe/H] = -3.41, [C/Fe] = +1.10

Neutron-capture element abundances are among the lowest in Milky Way halo stars

Provides improved upper limits for Y, Ba, Eu

Abstract

With [Fe/H] ~ -3.3, CD -24_17504 is a canonical metal-poor main sequence turn-off star. Though it has appeared in numerous literature studies, the most comprehensive abundance analysis for the star based on high resolution, high signal-to-noise spectra is nearly 15 years old. We present a new detailed abundance analysis for 21 elements based on combined archival Keck-HIRES and VLT-UVES spectra of the star that is higher in both spectral resolution and signal-to-noise than previous data. Our results for many elements are very similar to those of an earlier comprehensive study of the star, but we present for the first time a carbon abundance from the CH G-band feature as well as improved upper limits for neutron-capture species such as Y, Ba and Eu. In particular, we find that CD -24_17504 has [Fe/H] = -3.41, [C/Fe] = +1.10, [Sr/H] = -4.68 and [Ba/H] <= -4.46, making it a carbon enhanced metal-poor star with neutron-capture element abundances among the lowest measured in Milky Way halo stars.