                        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.

                               2021 October 14

                         NGC 7293: The Helix Nebula
               Image Credit & Copyright: Ignacio Diaz Bobillo

   Explanation: A mere seven hundred light years from Earth, toward the
   constellation Aquarius, a sun-like star is dying. Its last few thousand
   years have produced the Helix Nebula (NGC 7293), a well studied and
   nearby example of a Planetary Nebula, typical of this final phase of
   stellar evolution. A total of 90 hours of exposure time have gone in to
   creating this expansive view of the nebula. Combining narrow band image
   data from emission lines of hydrogen atoms in red and oxygen atoms in
   blue-green hues, it shows remarkable details of the Helix's brighter
   inner region about 3 light-years across. The white dot at the Helix's
   center is this Planetary Nebula's hot, central star. A simple looking
   nebula at first glance, the Helix is now understood to have a
   surprisingly complex geometry.

                     Tomorrow's picture: pixels in space
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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