A molecular jet in the pre-planetary nebula IRAS 19134+2131

Using the VLBA, we have observed water maser emission in the pre-planetary nebula candidate, IRAS 19134+2131 (I1913), in which the water maser spectrum has two groups of emission features separated in radial velocity by $∼$100${km s}$^{-1}$. The morphology and 3-D kinematics indicate the existence of a fast collimated flow with a dynamical age of only $∼$40 years. Such a "water fountain" source is a signature of the recent operation a stellar jet that may be responsible for the final shape of the planetary nebula into which I1913 is expected to evolve. We have also estimated the distance to I1913 on the basis of an annual parallax and the kinematics of IRAS 19134+2131 in our Galaxy. I1913 may be a component in the "thick disk" or the Galactic "warp", whose kinematics are different from those of the Galactic "thin" disk.