Line ratio diagnostic diagram for Fe gas phase depletion: [Fe ii] 1.64 μm/[O i] 6300 Å versus [Fe ii] 1.53/1.64 μm. [Fe ii] line fluxes are integrated over the same velocity and spatial intervals as [O i] fluxes from Lavalley-Fouquet et al. (2000). The three data points correspond to distances along the DG Tauri blueshifted jet of 025, 075 and 125 (increasing with decreasing [Fe ii] 1.53/1.64 μm). Full curves show predictions for volume emission at 8000 K (top panel) and for J-shocks (bottom panel) from Hartigan et al. (2004b) assuming an [Fe/O] solar gas phase abundance of 0.062 (Asplund et al. 2005). Dashed curves show [Fe/O] abundances required to reproduce observed line ratios. They indicate Fe gas phase depletion by a factor 3−4 for the IVB[–250, –100] km s^-1 and 10−12 for the LVB[–100, +10] km s^-1 intervals.