L. F. Miranda, M. Blanco, M. A. Guerrero, A. Riera
Hu\,1-2 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$\alpha$+[N\,{\sc ii}] image and a
high-resolution, long-slit spectrum of Hu\,1-2 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$\alpha$+[N\,{\sc ii}] CCD images, with a time baseline of $\simeq$ 57 yr. A
proper motion of 20 $\pm$ 6\,mas\,yr$^{-1}$ along position angle 312$^{\circ}$
$\pm$ 15$^{\circ}$, 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 Hu\,1-2.
View original:
http://arxiv.org/abs/1112.5007
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