Program: GN-2008A-DD-4

We are proposing for 1.5 hours of DD time (2.0hrs, including telluric calibration) to observe the J, H, and K-band NIFS spectra of the young star AA Tau to follow-up our very surprising finding of spatially resolved water vapor in the inner regions of the star's disk. Our 2007B program of the K-band NIFS spectrum of AA Tau has revealed tantalizing evidence for both water vapor absorption and *emission* from different spatial regions around the young star. The geometry of the features is consistent with it's known edge-on disk. If confirmed, this result could provide the first ever detection of spatially resolved water vapor emission in the inner < 5AU environments of a young star and would also allow for a spatially resolved study of the environment that gives rise to these poorly understood emissions. Detection of the key H2O features in the J and H band are needed to confirm the water, and they could provide a direct measure of the temperature of the absorbing gas. If successful, we envision this DD proposal could lead to a rapid turn-around ApJ Letter (or even a Nature article).