8.1. Gas Stripes near Planetary Nebulae
Some planetary nebulae seem to be located near gaseous stripes, with the orientation of the narrow (~ 0.1 pc), long (~ 2 pc) stripes being parallel to the Galactic Plane. The stripes could have come from stripping of the gas previously in the halo of planetary nebulae, due to the relative motion of the central star ~ 20 km/s. The stripes could also be ionized by the central star of the planetary nebulae at a distance ~ 0.5 pc away, and be oriented by the shape of the galactic magnetic field (~ 10-6 Gauss) reconnecting in the gas behind the planetary nebula's motion (e.g., Soker and Zucker 1997; Soker and Dgani 1997).