Synthetic spectrum of the CH band around 4315 Å. The black solid line represents the observed spectrum, while the blue dotted line shows the best-fit synthetic spectrum. The red short-dashed line and magenta long-dashed line correspond to synthetic spectra with Δ[C/Fe] = −0.2 and Δ[C/Fe] = +0.2, respectively. A zoomed-in view of the CH band region is shown in the upper panel.