Predictions for JWST-MIRI-MRS. (a) Comparison between Spitzer-IRS fluxes of the H₂O blend at 12.5 μm and our DALI models for two values of gas-to-dust mass ratio. Spitzer-IRS fluxes, represented by gray markers (triangles for upper limits and squares for detections), are well matched by dust-depleted disk atmospheres. The accretion luminosity is set to its fiducial value of L_acc = 0.12 L_⊙, recalling that L_acc has little effect on H₂O line fluxes. (b) OH line fluxes at 10.07 μm as a function of L_acc. For dust depletion factors in line with Spitzer-IRS water line fluxes and without considering MIRI-MRS fringes, OH is expected to be detected. (c) The contrast between the OH line at 10.07 μm and the continuum. The gray area shows the typical residual noise after a psff fringe correction (Gasman et al. 2023a) or calibration with observations of asteroids (Pontoppidan et al. 2024).