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.

                                2025 March 7
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                          Planetary Nebula Abell 7
         Image Credit: Image Credit & [3]Copyright: [4]Vikas Chander

   Explanation: Very faint planetary nebula Abell 7 is about 1,800
   light-years distant. It lies just south of Orion in planet Earth's
   skies toward the constellation [5]Lepus, The Hare. Surrounded by Milky
   Way stars and near the line-of-sight to distant background galaxies its
   [6]generally simple spherical shape, about 8 light-years in diameter,
   is revealed in this deep telescopic image. Within the cosmic cloud are
   beautiful and complex structures though, enhanced by the use of long
   exposures and [7]narrowband filters that capture emission from
   hydrogen, sulfur, and oxygen atoms. Otherwise Abell 7 would be much too
   faint to be appreciated [8]by eye. A [9]planetary nebula represents a
   very brief final phase in stellar evolution that our own Sun will
   experience 5 billion [10]years hence, as the nebula's central, once
   sun-like star shrugs off its outer layers. Abell 7 itself is estimated
   to be 20,000 years old. But its central star, seen here as a [11]fading
   white dwarf, is some 10 billion years old.

                      Tomorrow's picture: light-weekend
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    Authors & editors: [23]Robert Nemiroff ([24]MTU) & [25]Jerry Bonnell
                                 ([26]UMCP)
          NASA Official: Amber Straughn [27]Specific rights apply.
              [28]NASA Web Privacy Policy and Important Notices
                A service of: [29]ASD at [30]NASA / [31]GSFC,
                         [32]NASA Science Activation
                           & [33]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2503/Abell7_VChander4096.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://www.instagram.com/vikaschanderastrophotography/
   5. http://www.allthesky.com/constellations/big/lepus28vm-b.jpg
   6. http://arxiv.org/abs/1210.6226
   7. https://apod.nasa.gov/apod/ap111013.html
   8. https://apod.nasa.gov/apod/ap100506.html
   9. http://en.wikipedia.org/wiki/Planetary_nebula
  10. http://www.futuretimeline.net/beyond.htm
  11. https://www.nasa.gov/feature/goddard/2019/citizen-scientist-finds-ancient-white-dwarf-star-encircled-by-puzzling-rings
  12. https://apod.nasa.gov/apod/ap250306.html
  13. https://apod.nasa.gov/apod/archivepix.html
  14. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  15. https://apod.nasa.gov/apod/lib/aptree.html
  16. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  17. https://apod.nasa.gov/apod/calendar/allyears.html
  18. https://apod.nasa.gov/apod.rss
  19. https://apod.nasa.gov/apod/lib/edlinks.html
  20. https://apod.nasa.gov/apod/lib/about_apod.html
  21. http://asterisk.apod.com/discuss_apod.php?date=250307
  22. https://apod.nasa.gov/apod/ap250308.html
  23. http://www.phy.mtu.edu/faculty/Nemiroff.html
  24. http://www.phy.mtu.edu/
  25. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  26. http://www.astro.umd.edu/
  27. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  28. https://www.nasa.gov/about/highlights/HP_Privacy.html
  29. https://astrophysics.gsfc.nasa.gov/
  30. https://www.nasa.gov/
  31. https://www.nasa.gov/centers/goddard/
  32. https://science.nasa.gov/learners
  33. http://www.mtu.edu/