Pre-perihelion logarithmic production rate ratios for comet 2I/Borisov as a function of the log of the heliocentric distance (log r_H). Colors and symbols are the same as in Figure 5. Borisov’s C₂-to-CN production rate ratios greatly increased as the comet approached perihelion, while its dust production rate ratios as A(0°)fρ-to-CN peaked significantly before perihelion. The additional data are from A. Fitzsimmons et al. (2019), C. Opitom et al. (2019), E. Jehin et al. (2020b), H. W. Lin et al. (2020), Z. Xing et al. (2020), K. Aravind et al. (2021), and S. Deam et al. (2026).