Spectral segments from three representative sightlines for the C₂ (A-X) Phillips (2-0) band. HD 147889 (top) has the highest C₂ column density in our data sample. HD 23016 (middle) shows a tentative detection, as the strongest Q(4) line is still below the 3σ detection limit. We considered multiple rotational lines simultaneously when deciding about possible identifications. The C₂ molecules are detected in two velocity components in HD 161056 (bottom). The combined model (red) is plotted against the spectral data, while synthetic spectra for the two velocity components (blue and orange) are plotted separately with an offset. We focus on the spectral segments around the C₂ transitions, and the wavelength grid is hence discrete. Rotational lines being considered in each sightline may differ due to telluric interference and/or data quality. These rotational lines are labelled with vertical bars. The best-fit parameters for the kinetic temperature, T_kin, number density, n, and the column density of the velocity component, N, are listed in each panel.