Program: GN-2009B-Q-40

We propose to acquire K-band NIFS+Altair integral field spectroscopy of seven young Sun-like stars to map the emission from molecular hydrogen gas in their circumstellar environments. Recent theoretical studies predict that H2 gas in the very inner regions of YSO disks may extend out to spatial distances of 30-50AU from the central star (depending on excitation flux from the star). Gemini + NIFS Altair *can* spatially resolve this emission, if it exists. A pilot program was completed in semester 2007B which illustrates NIFS's ability to resolve faint H2 emission in the vicinity of bright young stars. The goal of the proposed observations is to establish the nature of the H2 gas in relation to the known circumstellar dust disk evolution and discover whether the H2 resides in the planet-forming regions of disks in these stars, or if it is found instead in outflows or wide-angle disk winds. Collectively, the proposed observations will spatially resolve the H2 emission, derive it's mass, place constraints on the excitation mechanism, and provide an important observational test of the persistence of H2 gas in the inner planet-forming environments of ~Myr Sun-like stars.