Astronomy Picture of the Day

   [1]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
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                         NGC 7293: The Helix Nebula
            Image Credit & [3]Copyright: [4]Ignacio Diaz Bobillo

   Explanation: A mere seven hundred light years from Earth, toward the
   constellation [5]Aquarius, a sun-like star is dying. Its last few
   thousand years have produced the [6]Helix Nebula (NGC 7293), a well
   studied and nearby example of a [7]Planetary Nebula, typical of this
   final phase of stellar evolution. A total of 90 hours of exposure time
   have gone in to creating [8]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
   [9]details of the Helix's brighter [10]inner region about 3 light-years
   across. The white dot at the Helix's center is this Planetary Nebula's
   hot, [11]central star. A simple looking nebula at [12]first glance, the
   Helix is now understood to have a surprisingly [13]complex geometry.

                     Tomorrow's picture: pixels in space
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    Authors & editors: [25]Robert Nemiroff ([26]MTU) & [27]Jerry Bonnell
                                 ([28]UMCP)
          NASA Official: Phillip Newman [29]Specific rights apply.
              [30]NASA Web Privacy Policy and Important Notices
                A service of: [31]ASD at [32]NASA / [33]GSFC
                           & [34]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2110/Helix_Oxygen_crop2.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. http://www.pampaskies.com/gallery3/index.php
   5. http://hawastsoc.org/deepsky/aqr/index.html
   6. https://en.wikipedia.org/wiki/Helix_Nebula
   7. http://en.wikipedia.org/wiki/Planetary_nebula
   8. http://www.pampaskies.com/gallery3/Deep-Space-Objects/Helix_Oxygen_crop2_small
   9. https://apod.nasa.gov/apod/ap080413.html
  10. https://apod.nasa.gov/apod/ap030510.html
  11. https://hubblesite.org/contents/media/images/2003/11/1317-Image.html
  12. https://apod.nasa.gov/apod/ap091231.html
  13. https://hubblesite.org/contents/news-releases/2004/news-2004-32.html
  14. https://apod.nasa.gov/apod/ap211013.html
  15. https://apod.nasa.gov/apod/archivepix.html
  16. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  17. https://apod.nasa.gov/apod/lib/aptree.html
  18. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  19. https://apod.nasa.gov/apod/calendar/allyears.html
  20. https://apod.nasa.gov/apod.rss
  21. https://apod.nasa.gov/apod/lib/edlinks.html
  22. https://apod.nasa.gov/apod/lib/about_apod.html
  23. http://asterisk.apod.com/discuss_apod.php?date=211014
  24. https://apod.nasa.gov/apod/ap211015.html
  25. http://www.phy.mtu.edu/faculty/Nemiroff.html
  26. http://www.phy.mtu.edu/
  27. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  28. http://www.astro.umd.edu/
  29. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  30. https://www.nasa.gov/about/highlights/HP_Privacy.html
  31. https://astrophysics.gsfc.nasa.gov/
  32. https://www.nasa.gov/
  33. https://www.nasa.gov/centers/goddard/
  34. http://www.mtu.edu/