Ba II line at 5853 Å. In the upper panels, we show the observed spectra with a black line. The purple line is actually two nearly identical profiles, computed for pure s- and pure r-process hfs, respectively; in the lower panels, the residuals between synthetic spectra and observed spectra are reported. In the left panels, we present the results for HD 6268, and on the right we show those for HD 4306.