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). via NASA https://ift.tt/324JHrZ

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