Spectral fitting of the Th II lines at 3469.92 Å (left panel) and 4019.13 Å (right panel) is shown for the CEMP-rs stars HD 187861, HD 224959, and CS 22891-171. Red lines correspond to spectral syntheses with the adopted Th II abundances of −0.65 for CS 22891-171 and −0.70 for HD 187861 in the left panels, and −0.85 dex for HD 187861 and −0.95 dex for HD 224959 in the right panels. Blue and green lines correspond to syntheses with abundances deviating by ±0.3 dex from the adopted abundance. The black dashed line represents the observed spectrum. The magenta line corresponds to the synthesis with a null Th abundance. The blue dashed line represents the synthetic spectrum excluding ¹³CH contributions, while the red dashed line excludes both ¹³CH and Th II contributions.