The Disruption of the Dense Disk in CRL 618

High angular resolution (0".066) 23 GHz observations of the radio continuum and NH3 (3,3) line absorption toward the protoplanetary nebula CRL 618 are presented. The (3,3) line is detected in absorption toward the continuum source. The absorption line profile shows multiple blended velocity components, symmetrically placed with respect to the approaching part of the expanding asymptotic giant branch envelope, -40 km s-1. Kinetic temperatures and column density images reveal for the first time the presence of a hot (≳200 K) and dense (∼107 cm-3) ridge perpendicular to the bipolar molecular outflow. Hot filamentary structures are also observed along the outflow. All the observational features, the gradient in the radial velocities, the systematic behavior of the line widths observed in the (3,3) line, as well as the derived kinetic temperature gradients, are explained by a model in which the NH3 lines arise from postshocked clumps produced when the fast stellar wind from the central star impinges on the inner regions of the circumstellar disk responsible for collimating the molecular outflow.