* Astronomy

Title: The collimated outflows of the planetary nebula Hu1-2: proper motion and radial velocity measurements
Authors: L. F. Miranda, M. Blanco, M. A. Guerrero, A. Riera

Hu1-2 is a planetary nebula that contains an isolated knot located northwestern of the main nebula, which could be related to a collimated outflow. We present a subsarcsecond H\alpha+[Nii] image and a high-resolution, long-slit spectrum of Hu1-2 that allow us to identify the southeastern counterpart of the northwestern knot and to establish their high velocity (> 340 km\,s^-1), collimated bipolar outflow nature. The detection of the northwestern knot in POSS red plates allows us to carry out a proper motion analysis by combining three POSS red plates and two narrow-band H\alpha+[Nii] CCD images, with a time baseline of \simeq 57 yr. A proper motion of 20 ± 6\,mas\,yr^-1 along position angle 312° ± 15°, and a dynamical age of 1375^{+590}\llap{_{-320}}\,yr are obtained for the bipolar outflow. The measured proper motion and the spatio-kinematical properties of the bipolar outflow yield a lower limit of 2.7 kpc for the distance to Hu1-2.

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