Thorium-rich halo star HD 221170: Further evidence against the universality of the r-process

Abstract

We report the abundance determination in the atmosphere of the bright halo star HD 221170. The spectra were taken with the Terskol Observatory's 2.0-m telescope with a resolution 45 000 and signal-to-noise ratio up to 250 in the wavelength region 3638–10 275 Å. The adopted atmospheric parameters correspond to an effective temperature = 4475 K, a surface gravity = 1.0, a microturbulent velocity = 1.7 , and a macroturbulent velocity = 4 . The abundances of 43 chemical elements were determined with the method of spectrum synthesis. The large overabundances (by 1 dex relative to iron) of elements with Z > 38 are shown to follow the same pattern as the solar r-abundances. The present HD 221170 analysis confirms the non-universality of the r-process, or more exactly the observation that the astrophysical sites hosting the r-process do not always lead to a unique relative abundance distribution for the bulk Ba to Hg elements, the Pb-peak elements, and the actinides.