Astronomy Picture of the Day

    Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                               2020 August 14

               NGC 5189: An Unusually Complex Planetary Nebula
    Image Credit: NASA, ESA, Hubble, HLA; Reprocessing & Copyright: Jesús
                                  M. Vargas

   Explanation: Why is this nebula so complex? When a star like our Sun is
   dying, it will cast off its outer layers, usually into a simple overall
   shape. Sometimes this shape is a sphere, sometimes a double lobe, and
   sometimes a ring or a helix. In the case of planetary nebula NGC 5189,
   however, besides an overall "Z" shape (the featured image is flipped
   horizontally and so appears as an "S"), no such simple structure has
   emerged. To help find out why, the Earth-orbiting Hubble Space
   Telescope has observed NGC 5189 in great detail. Previous findings
   indicated the existence of multiple epochs of material outflow,
   including a recent one that created a bright but distorted torus
   running horizontally across image center. Hubble results appear
   consistent with a hypothesis that the dying star is part of a binary
   star system with a precessing symmetry axis. NGC 5189 spans about three
   light years and lies about 3,000 light years away toward the southern
   constellation of the Fly (Musca).

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