Synthetic spectrum of the C₂ band around 5165 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 C₂ band region is shown in the upper panel.