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.

                               2019 October 25
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                          The Ghosts of Cassiopeia
                 Image Credit & [3]Copyright: Tommaso Stella

   Explanation: These bright rims and flowing shapes look ghostly on a
   cosmic scale. A telescopic view toward the constellation [4]Cassiopeia,
   the colorful skyscape features swept-back, comet-shaped clouds IC 59
   (left) and IC 63. About 600 light-years distant, [5]the clouds aren't
   actually ghosts. They are slowly disappearing though, under the
   influence of [6]energetic radiation from hot,luminous star gamma Cas.
   [7]Gamma Cas is physically located only 3 to 4 light-years from the
   nebulae, the bright star just above and left in the frame. Slightly
   closer to gamma Cas, IC 63 is dominated by [8]red H-alpha light emitted
   as hydrogen atoms ionized by the star's ultraviolet radiation recombine
   with electrons. Farther from the star, IC 59 shows proportionally less
   H-alpha emission but more of the characteristic blue tint of dust
   [9]reflected star light. The field of view spans over 1 degree or 10
   light-years at the estimated distance of [10]gamma Cas and friends.

                     Tomorrow's picture: only the smile
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    Authors & editors: [22]Robert Nemiroff ([23]MTU) & [24]Jerry Bonnell
                                 ([25]UMCP)
          NASA Official: Phillip Newman [26]Specific rights apply.
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                A service of: [28]ASD at [29]NASA / [30]GSFC
                           & [31]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/1910/IC59IC63TheGhostsOfCassiopeiaTommasoStella2019.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://apod.nasa.gov/apod/ap160318.html
   5. http://iopscience.iop.org/1538-3881/129/2/954
   6. https://arxiv.org/abs/1809.01419
   7. https://www.aavso.org/vsots_gammacas
   8. https://apod.nasa.gov/apod/ap111013.html
   9. https://apod.nasa.gov/apod/ap091126.html
  10. https://arxiv.org/abs/1705.04313
  11. https://apod.nasa.gov/apod/ap191024.html
  12. https://apod.nasa.gov/apod/archivepix.html
  13. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  14. https://apod.nasa.gov/apod/lib/aptree.html
  15. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  16. https://apod.nasa.gov/apod/calendar/allyears.html
  17. https://apod.nasa.gov/apod.rss
  18. https://apod.nasa.gov/apod/lib/edlinks.html
  19. https://apod.nasa.gov/apod/lib/about_apod.html
  20. http://asterisk.apod.com/discuss_apod.php?date=191025
  21. https://apod.nasa.gov/apod/ap191026.html
  22. http://www.phy.mtu.edu/faculty/Nemiroff.html
  23. http://www.phy.mtu.edu/
  24. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  25. http://www.astro.umd.edu/
  26. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  27. https://www.nasa.gov/about/highlights/HP_Privacy.html
  28. https://astrophysics.gsfc.nasa.gov/
  29. https://www.nasa.gov/
  30. https://www.nasa.gov/centers/goddard/
  31. http://www.mtu.edu/