Metallicities of the C-19 members. (a) Comparison of the metallicities derived from the two methods for the same spectra of the nine stars that have high S/N HR spectra. The symbols are color coded by S/N₁ (Table 1). (b) Comparison of the metallicities derived from the HR spectra using Fe lines and the low-to-medium spectra using Ca triplet equivalent widths for three C-19 stars. The two existing member stars in Yuan et al. (2022b) with VLT/UVES spectra are plotted with yellow symbols and the new member with a Subaru/HDS spectrum is shown in magenta. (c) MDFs of [Fe/H] (blue) and [Fe/H]_CaT (orange) in this work compared to the MDF of [FeI/H] of the existing C-19 members from Yuan et al. (2022b).