Spectral dependence of the P_r of T2 and other OCCs: C/1995 Ol (Hale–Bopp) and 1P/Halley. Measurements for other OCCs were obtained from the NASA/PDS comet Polarimetrie archive (Kiselev et al. 2017): Hale-Bopp from Hasegawa et al. (1997) and 1P/Halley from Brooke et al. (1987) with squares and Kikuchi et al. (1987) with diamonds, whose phase angles are given in parentheses. The horizontal bars cover the J and H bands, while the vertical bars indicate errors in the average value of all data points in each band.