Ammonia in the Kleinmann-Low nebula

Ammonia is observed toward the Kleinmann-Low nebula via the microwave radiation from the inversion doublets of the six lowest metastable rotational states. Hyperfine structures were detected in the three lowest transitions, from which optical depths on the order of 1--2 are derived. Assuming usual values for density and temperature, this implies that the ammonia molecules must be ''clumped'' with a filling factor Phi<0.04 with respect to a 1'.4 beam. The effect of radiative trapping is to lower the upper limit on Phi. We have detected a low-velocity feature at 3.8 km s-1, less by a factor of 4 in line intensity than the 8 km s-1 main feature, in the (1,1) line. This feature appears to be present in all six transitions observed