The molecular outflow and possible precessing jet from the massive young stellar object IRAS 20126+4104

We present images of the molecular gas in the IRAS 20126+4104 massive outflow and examine the interaction between the energetic outflowing material and the surrounding molecular cloud. Mosaic interferometric images in CO(1-0), (CO)-C-13(1-0), (CO)-O-18(1-0), (CO)-O-17(1-0), and millimeter continuum emission are compared with mid-infrared images at 12.5 and 17.9 mu m, near-infrared images in the K, band (2.17 mu m) and H-2 line emission, and optical H alpha and [S II] images. We show that the molecular outflow is approximately 6 x 10(4) yr old with a mass of about 50-60 M. and mass outflow rate (M) over dot(f) similar to 8 x 10(-4) M. yr(-1). The driving source is located near the center of the greater than or similar to 300 Mo molecular cloud, and the mass of the disk plus circumstellar envelope traced by millimeter continuum emission is similar to 50 M.. The outflow appears to be bounded on most sides by higher density gas traced by (CO)-O-18 emission. Shocks identified by H-2 and [S II] emission knots follow a NW-SE jet close to the young stellar object and then rotate more north-south along the edges of the CO flow. The most likely interpretation appears to be that the knots trace the working surfaces of a collimated jet that precesses through an angle of similar to 45 degrees. Possible mechanisms that could produce the jet precession include tidal interactions between the disk and a companion star in a noncoplanar orbit or an anisotropic accretion event that dramatically altered the angular momentum vector of the disk.