The Hubble 12 Nebula (PN Hb 12) is a bipolar nebulae in the Cassiopeia constellation. The shape of this nebula, like a butterfly or an hourglass, was formed as a Sun-like star approached the end of its life and puffed its outer layers into the surrounding space. For bipolar nebulae, this material is funneled towards the poles of the aging star, creating the distinctive double-lobed structure.
NASA's Hubble Space Telescope and also the New Technology Telescope show that bipolar planetary nebulae located towards the central bulge of our Milky Way appear to be strangely aligned in the sky. The similarities of this result are surprising given the varied and chaotic formations of nebulae.
Photo : NASA HST, ESA, A. Zijlstra (The University of Manchester), and J. Barrington (Hubble's Hidden Treasures Competition)