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.

2012 December 19
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NGC 5189: An Unusually Complex Planetary Nebula
Image Credit: NASA, ESA, Hubble Heritage Team (STScI/AURA)

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, no such simple structure has emerged. To help find out why, the Earth-orbiting Hubble Space Telescope recently 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. Results appear consistent with a hypothesis that the dying star is part of a binary star system with a precessing symmetry axis. Given this new data, though, research is sure to continue. NGC 5189 spans about three light years and lies about 3,000 light years away toward the southern constellation of the Fly (Musca).

APOD Editors to Speak: RJN in Philadelphia on Jan. 3 & JTB in New York City on Jan. 4
Tomorrow's picture: triangulum

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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