                        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.

                                2025 April 16
       A dark starfield is dominated by a green nebula with intricate
     filaments all around. At the center is a bright glow surrounding a
   central star. Please see the explanation for more detailed information.

                            Halo of the Cat's Eye
       Image Credit & Copyright: Taavi Niittee (Tõrva Astronomy Club)

   Explanation: What created the unusual halo around the Cat's Eye Nebula?
   No one is sure. What is sure is that the Cat's Eye Nebula (NGC 6543) is
   one of the best known planetary nebulae on the sky. Although haunting
   symmetries are seen in the bright central region, this image was taken
   to feature its intricately structured outer halo, which spans over
   three light-years across. Planetary nebulae have long been appreciated
   as a final phase in the life of a Sun-like star. Only recently however,
   have some planetaries been found to have expansive halos, likely formed
   from material shrugged off during earlier puzzling episodes in the
   star's evolution. While the planetary nebula phase is thought to last
   for around 10,000 years, astronomers estimate the age of the outer
   filamentary portions of the Cat's Eye Nebula's halo to be 50,000 to
   90,000 years.

                      Tomorrow's picture: star cylinder
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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