  A search for H3+ line emission, reported to have been detected toward the
young star HD 141569A and possibly originating in a clump of planet-forming gas
orbiting the star, has yielded negative results. Observations made at the
United Kingdom Infrared Telescope and at the Subaru Telescope during 2001-2005
covered 11 major transitions of H3+ from 3.42 to 3.99 um. No H3+ emission lines
were detected; one marginal detection at 3.9855 um in June 2002 was not
confirmed in later spectra. The upper limits to the line strengths are
significantly lower than the previously reported detections. Supplemental
slit-scanning spectroscopy using adaptive optics was performed within 0.38 of
HD 141569A to search for extended emission from H3+, but no emission was
detected. We compare our upper limit to the luminosity in H3+ from HD 141569A
with that possible from a gas giant protoplanet and also from a jovian mass
exoplanet in close orbit about its central star.
