Panel a: integrated flux of the CN (N,J) = (3−2, 7/2−5/2) emission in a T Tauri disk with M_gas = 10^-2M_⊙, ψ = 0.2, and h_c = 0.1 as a function of the accretion rate on the central star. For each accretion rate, the UV luminosity between 91.2 and 110 nm is also shown at the top of the figure. The standard model (Ṁ = 10^-8M_⊙ yr^-1) is marked with a blue square. Panel b: same as panel a, for the CN ring radius.