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 June 9
    [2]A starfield is shown with many stars and several faint light brown
     dust clouds. In the center is a large cloud with brown dust and gas
     shells lined in blue. Please see the explanation for more detailed
                                information.

           Between Scylla and Charybdis: A Double Cosmic Discovery
      Image Credit: M. Drechsler, Y. Sainty, A. Soto, N. Martino, [3]L.
      Leroux-Gere, S. Khallouqui, & A. Kaeouach; Text: [4]Ogetay Kayali
                            ([5]Michigan Tech U.)

   Explanation: Can you identify this celestial object? Likely not —
   because this is a [6]discovery image. Massive stars forge heavy
   elements in their cores and, after a few million years, end their lives
   in powerful [7]supernova explosions. These [8]remnants cool relatively
   quickly and fade, making them difficult to detect. To uncover such
   faint, previously unknown supernova remnants, a dedicated group of
   amateur astrophotographers searched through [9]sky surveys for possible
   supernova remnant candidates. The result: the first-ever image of
   supernova remnant G115.5+9.1 — named Scylla by its discoverers—glowing
   faintly in the constellation of the mythological King of Aethiopia:
   Cepheus. Emission from [10]hydrogen atoms in the remnant is shown in
   red, and faint [11]emission from oxygen is shown in hues of blue.
   Surprisingly, another discovery lurked to the upper right: a faint,
   previously unknown [12]planetary nebula candidate. In keeping with
   mythological tradition, it was named Charybdis (Sai 2) — a nod to the
   ancient Greek expression "caught [13]between Scylla and Charybdis" from
   [14]Homer’s Odyssey.

                     Tomorrow's picture: leaky space orb
     __________________________________________________________________

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     __________________________________________________________________

    Authors & editors: [26]Robert Nemiroff ([27]MTU) & [28]Jerry Bonnell
                                 ([29]UMCP)
          NASA Official: Amber Straughn [30]Specific rights apply.
            [31]NASA Web Privacy, [32]Accessibility, [33]Notices;
                A service of: [34]ASD at [35]NASA / [36]GSFC,
                         [37]NASA Science Activation
                           & [38]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2506/ScyllaB_LerouxGere_2094.jpg
   3. https://www.astrobin.com/users/Lrx.photo/
   4. https://scholar.google.com/citations?user=WYB79r4AAAAJ&hl=en
   5. https://www.mtu.edu/physics/
   6. https://www.astrobin.com/280z5s/
   7. https://apod.nasa.gov/apod/ap250508.html
   8. https://apod.nasa.gov/apod/ap250117.html
   9. https://archive.eso.org/dss/dss
  10. https://en.wikipedia.org/wiki/Hydrogen-alpha
  11. https://en.wikipedia.org/wiki/Doubly_ionized_oxygen
  12. https://planetarynebulae.net/EN/
  13. https://en.wikipedia.org/wiki/Between_Scylla_and_Charybdis
  14. https://en.wikipedia.org/wiki/Odyssey
  15. https://apod.nasa.gov/apod/ap250608.html
  16. https://apod.nasa.gov/apod/archivepix.html
  17. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  18. https://apod.nasa.gov/apod/lib/aptree.html
  19. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  20. https://apod.nasa.gov/apod/calendar/allyears.html
  21. https://apod.com/feed.rss
  22. https://apod.nasa.gov/apod/lib/edlinks.html
  23. https://apod.nasa.gov/apod/lib/about_apod.html
  24. https://asterisk.apod.com/discuss_apod.php?date=250609
  25. https://apod.nasa.gov/apod/ap250610.html
  26. http://www.phy.mtu.edu/faculty/Nemiroff.html
  27. http://www.phy.mtu.edu/
  28. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  29. http://www.astro.umd.edu/
  30. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  31. https://www.nasa.gov/about/highlights/HP_Privacy.html
  32. https://www.nasa.gov/general/accessibility/
  33. https://www.nasa.gov/privacy/
  34. https://astrophysics.gsfc.nasa.gov/
  35. https://www.nasa.gov/
  36. https://www.nasa.gov/centers/goddard/
  37. https://science.nasa.gov/learners
  38. http://www.mtu.edu/