Error Analysis of Light n-Capture Element Abundances in the Metal-Poor Halo Star HD74462

Abstract

ABSTRACTThe origin of light neutron-capture elements in the early Galaxy is an unsolved problem of nuclear astrophysics. Previous studies have not been able to provide a satisfactory mechanism for the production of elements such as zirconium (Zr), yttrium (Y), and strontium (Sr) in the early Galaxy. In a previous article, these elements were studied using high-resolution spectra to reduce uncertainty. Determining the abundances of elements in distant stars requires the use of computer models of the stellar atmosphere. We now analyze the impacts of possible errors in those computational models on the calculated elemental abundance in the star. By adjusting model parameters for the prototypical metal-poor halo star HD074462—specifically: effective temperature, microturbulent velocity, surface gravity, and metallicity—we can judge the relative sensitivity of our calculations to errors in these values. Four lines of Zr, as well as five lines of Y, were observed in this article. Our findings show that the calculated elemental abundance is most sensitive to errors in the effective temperature of the star, while microturbulent velocity had little-to-no effect. Errors in surface gravity and metallicity of ± 0.5 dex caused a wider variety of errors in the abundance value, with none greater than 0.25 dex.