  We report on the first results of a search for H2 emission from
protoplanetary disks using CRIRES, ESO's new VLT high resolution NIR
spectrograph. We observed the CTTS LkHa 264 and the debris disk 49 Cet, and
searched for the 1-0 S(1), 1-0 S(0) and 2-1 S(1) H2 emission lines. The H2 line
at 2.1218 micron is detected in LkHa 264. Our CRIRES spectra reveal the
previously observed but not detected H2 line at 2.2233 micron in LkHa 264. An
upper limit on the 2-1 S(1) H2 line flux in LkHalpha 264 is derived. These
observations are the first simultaneous detection of 1-0 S(1) and 1-0 S(0) H2
emission from a protoplanetary disk. 49 Cet does not exhibit H2 emission in any
of the three observed lines. There are a few lunar masses of optically thin hot
H2 in the inner disk (~0.1 AU) of LkHa 264, and less than a tenth of a lunar
mass of hot H2 in the inner disk of 49 Cet. The measured 1-0 S(0)/1-0 S(1) and
2-1 S(1)/1-0 S(1) line ratios in LkHa 264 indicate that the H2 emitting gas is
at T<1500 K and that the H2 is most likely thermally excited by UV photons.
Modeling of the shape of the line suggests that the disk should be seen close
to face-on (i<35). A comparative analysis of the physical properties of CTTS in
which the H2 1-0 S(1) line has been detected and non-detected indicates that
the presence of H2 emission is correlated with the magnitude of the UV excess
and the strength of the Halpha line. The lack of H2 emission in the NIR spectra
of 49 Cet and the absence of Halpha emission suggest that the gas in the inner
disk of 49 Cet has dissipated. The disk surrounding 49 Cet should have an inner
hole.
