H2O and OH gas in the terrestrial planet-forming zones of protoplanetary disks

We present detections of numerous 10-20 mu m H(2)O emission lines from two protoplanetary disks around the T Tauri stars AS 205A and DR Tau, obtained using the InfraRed Spectrograph on the Spitzer Space Telescope. Followup 3-5 mu m Keck NIRSPEC data confirm the presence of abundant water and spectrally resolve the lines. We also detect the P4.5 (2.934 mu m) and P9.5 (3.179 mu m) doublets of OH and (12)CO/(13)CO nu = 1 -> 0 emission in both sources. Line shapes and LTE models suggest that the emission from all three molecules originates between similar to 0.5 and 5 AU, and so will provide a new window for understanding the chemical environment during terrestrial planet formation. LTE models also imply significant columns of H(2)O and OH in the inner disk atmospheres, suggesting physical transport of volatile ices either vertically or radially, while the significant radial extent of the emission stresses the importance of a more complete understanding of nonthermal excitation processes.