Figure 9

Figure 9

CO v=1-0 R(3) emission in two pre-main sequence spectroscopic binaries, obtained at the IRTF with CSHELL at a resolution of 20,000 (observations by J. Carr, R. Mathieu, and J. Najita). These systems show evidence for active accretion disks, but dynamical theory predicts the presence of tidally cleared gaps in the disks. In the case of GW Ori, an observed dip in the spectral energy distribution at mid-infrared wavelengths provides evidence for a disk gap centered at the secondary distance of 1 AU (Mathieu, Adams & Latham 1991). The fundamental CO emission lines from GW Ori indicate an average rotational temperature of 700K. Both narrow (unresolved) and broad velocity components are observed; their velocity widths are consistent with gas at radii exterior and interior to the gap, respectively. In the case of DQ Tau, the velocity width is consistent with gas just outside of the expected gap.