Chemical abundance analysis of HE 2324-0215, an r-process-enhanced metal-poor star

Abstract

We report the abundance analysis of the metal-poor halo star HE 2324-0215 for 22 neutron-capture elements and 14 light elements with Z < 30. The stellar parameters are [Fe/H] = -3.05 ± 0.17, Teff = 4477 K, Vt = 2.70 kms-1 , and log(g) = 0.70, indicating that HE 2324-0215 is a red giant star. The [Eu/Fe] = 0.73 and [Ba/Eu] = -0.68 suggests that this is an r-I star. Since thorium is detectable in this star, we derived the age of the star by the means of radioactive decay, resulting in the age of 13.0 ± 1.0 Gyr. The age and the metallicity of the star suggest that HE 2324-0215 formed in a dwarf galaxy which was later accreted and became part of the Milky Way.