Location of the CO v = 1 − 0 J = 19 − 18 P(19) at 4.844 μm and CO v = 4 − 3 J = 20 − 19 P(20) at 4.692 μm line emissions for the M_disc = 10^-2M_⊙, R_in = 1 AU disc models with (left panels, model 1a) and without (right panels, model 1b) UV pumping. The solid black contours in the CO density panels encompass the regions that emit 49% of the fluxes. The black dashed-line contours contain 70% of the fluxes in the vertical direction. The white contours are at gas temperatures of 500 and 1000 K. Each panel is divided into three sub-panels. The upper sub-panels show in color scale the atomic hydrogen density structure, the middle-panels show the molecular hydrogen density structure, and the lower-panels show the electron density structure.