  We report high resolution NIR spectroscopy of CO and OH emission from the
Herbig Be star HD100546. We discuss how our results bear striking resemblance
to several theoretically predicted signposts of giant planet formation. The
properties of the CO and OH emission lines are consistent with our earlier
interpretation that these diagnostics provide indirect evidence for a companion
that orbits the star close to the disk wall (at ~13au). The asymmetry of the OH
spectral line profiles and their lack of time variability are consistent with
emission from gas in an eccentric orbit at the disk wall that is approximately
stationary in the inertial frame. The time variable spectroastrometric
properties of the CO v=1-0 emission line point to an orbiting source of CO
emission with an emitting area similar to that expected for a circumplanetary
disk (~0.1au^2) assuming the CO emission is optically thick. We also consider a
counterhypothesis to this interpretation, namely that the variable CO emission
arises from a bright spot on the disk wall. We conclude with a brief suggestion
of further work that can distinguish between these scenarios.
