The Evolution of Protoplanetary Disks: Probing the Inner Disk of Very
  Low Accretors
  We report FUV, optical, and NIR observations of three T Tauri stars in the
Orion OB1b subassociation with H$\alpha$ equivalent widths consistent with low
or absent accretion and various degrees of excess flux in the mid-infrared. We
aim to search for evidence of gas in the inner disk in HST ACS/SBC spectra, and
to probe the accretion flows onto the star using H$\alpha$ and He I
$\lambda$10830 in spectra obtained at the Magellan and SOAR telescopes. At the
critical age of 5 Myr, the targets are at different stages of disk evolution.
One of our targets is clearly accreting, as shown by redshifted absorption at
free-fall velocities in the He I line and wide wings in H$\alpha$; however, a
marginal detection of FUV H$_2$ suggests that little gas is present in the
inner disk, although the spectral energy distribution indicates that small dust
still remains close to the star. Another target is surrounded by a transitional
disk, with an inner cavity in which little sub-micron dust remains. Still, the
inner disk shows substantial amounts of gas, accreting onto the star at a
probably low, but uncertain rate. The third target lacks both a He I line or
FUV emission, consistent with no accretion or inner gas disk; its very weak IR
excess is consistent with a debris disk. Different processes occurring in
targets with ages close to the disk dispersal time suggest that the end of
accretion phase is reached in diverse ways.
