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.

                                2024 April 30
   [2]A faint nebula runs vertically in the image. In the center is a red
    envelope surrounding diffuse blue emission. In the center is a bright
   multicolored nebula that is nearly circular. Please see the explanation
                       for more detailed information.

                      GK Per: Nova and Planetary Nebula
              Image Credit & Copyright: [3]Deep Sky Collective

   Explanation: The star system GK Per is known to be associated with only
   two of the three nebulas [4]pictured. At 1500 [5]light years distant,
   Nova Persei 1901 ([6]GK Persei) was the second closest [7]nova yet
   recorded. At the very center is a [8]white dwarf star, the surviving
   core of a former Sun-like star. It is surrounded by the circular
   [9]Firework nebula, gas that was ejected by a [10]thermonuclear
   explosion on the white dwarf's surface -- a nova -- as [11]recorded in
   1901. The red glowing gas surrounding the Firework nebula is the
   atmosphere that used to surround the central star. This gas was
   expelled before the [12]nova and appears as a diffuse [13]planetary
   nebula. The [14]faint gray gas running across is [15]interstellar
   cirrus that seems to be [16]just passing through coincidently. In 1901,
   GK Per's nova [17]became brighter than [18]Betelgeuse. Similarly, star
   system [19]T CrB is expected to erupt in a nova later this year, but we
   don't know exactly when nor [20]how bright it will become.

                        Tomorrow's picture: sky fish
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    Authors & editors: [32]Robert Nemiroff ([33]MTU) & [34]Jerry Bonnell
                                 ([35]UMCP)
          NASA Official: Amber Straughn [36]Specific rights apply.
            [37]NASA Web Privacy, [38]Accessibility, [39]Notices;
                A service of: [40]ASD at [41]NASA / [42]GSFC,
                         [43]NASA Science Activation
                           & [44]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2404/GKPerWide_DSC_4329.jpg
   3. https://deepskycollective.com/
   4. https://www.astrobin.com/ocm8rv/
   5. https://spaceplace.nasa.gov/light-year/
   6. https://en.wikipedia.org/wiki/GK_Persei
   7. https://en.wikipedia.org/wiki/Nova
   8. https://science.nasa.gov/universe/stars/types/#white-dwarfs
   9. https://apod.nasa.gov/apod/ap980704.html
  10. https://youtu.be/11e8XyUBqRQ
  11. https://www.aavso.org/vsots_gkper
  12. https://youtu.be/zYmd8EETy74
  13. https://apod.nasa.gov/apod/ap230416.html
  14. https://deepskycollective.com/gkpersei/lrgbhoo
  15. https://www.cosmotography.com/images/galactic_cirrus.html
  16. https://arxiv.org/abs/2201.10332
  17. https://media.zenfs.com/en_US/News/BGR_News/scared-surprised-cat-face.jpg
  18. https://apod.nasa.gov/apod/ap200511.html
  19. https://blogs.nasa.gov/Watch_the_Skies/2024/02/27/view-nova-explosion-new-star-in-northern-crown/
  20. https://en.wikipedia.org/wiki/T_Coronae_Borealis
  21. https://apod.nasa.gov/apod/ap240429.html
  22. https://apod.nasa.gov/apod/archivepix.html
  23. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  24. https://apod.nasa.gov/apod/lib/aptree.html
  25. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  26. https://apod.nasa.gov/apod/calendar/allyears.html
  27. https://apod.com/feed.rss
  28. https://apod.nasa.gov/apod/lib/edlinks.html
  29. https://apod.nasa.gov/apod/lib/about_apod.html
  30. https://asterisk.apod.com/discuss_apod.php?date=240430
  31. https://apod.nasa.gov/apod/ap240501.html
  32. http://www.phy.mtu.edu/faculty/Nemiroff.html
  33. http://www.phy.mtu.edu/
  34. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  35. http://www.astro.umd.edu/
  36. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  37. https://www.nasa.gov/about/highlights/HP_Privacy.html
  38. https://www.nasa.gov/general/accessibility/
  39. https://www.nasa.gov/privacy/
  40. https://astrophysics.gsfc.nasa.gov/
  41. https://www.nasa.gov/
  42. https://www.nasa.gov/centers/goddard/
  43. https://science.nasa.gov/learners
  44. http://www.mtu.edu/