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 April 27
    [2]A complex orange and purple nebula with a complex texture is shown
      in front of a dark starfield. Please see the explanation for more
                            detailed information.

                        IC 418: The Spirograph Nebula
       Image Credit: [3]NASA, [4]ESA, and the [5]Hubble Heritage Team
      ([6]STScI/[7]AURA); Acknowledgement: [8]R. Sahai ([9]JPL) et al.

   Explanation: What is creating the strange texture of IC 418? Dubbed the
   [10]Spirograph Nebula for its resemblance to drawings from a
   [11]cyclical drawing tool, [12]planetary nebula IC 418 shows
   [13]patterns that are not well understood. Perhaps they are related to
   chaotic [14]winds from the variable central star, which [15]changes
   brightness unpredictably in just a few hours. By contrast, evidence
   indicates that only a few million years ago, [16]IC 418 was probably a
   well-understood star similar to our [17]Sun. Only a few thousand years
   ago, [18]IC 418 was probably a common [19]red giant star. Since running
   out of [20]nuclear fuel, though, the outer envelope has begun expanding
   outward leaving a [21]hot remnant core destined to become a
   [22]white-dwarf star, visible in the image center. The light from the
   central core excites surrounding [23]atoms in the [24]nebula causing
   them to glow. [25]IC 418 lies about 2000 [26]light-years away and spans
   0.3 light-years across. [27]This false-color image taken from the
   [28]Hubble Space Telescope reveals the [29]unusual details.

                  Tomorrow's picture: interstellar tadpoles
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    Authors & editors: [41]Robert Nemiroff ([42]MTU) & [43]Jerry Bonnell
                                 ([44]UMCP)
          NASA Official: Amber Straughn [45]Specific rights apply.
            [46]NASA Web Privacy, [47]Accessibility, [48]Notices;
                A service of: [49]ASD at [50]NASA / [51]GSFC,
                         [52]NASA Science Activation
                           & [53]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2504/Spirograph_Hubble_2119.jpg
   3. https://www.nasa.gov/
   4. https://esahubble.org/
   5. https://www.nasa.gov/stem-content/the-hubble-heritage-project/
   6. https://www.stsci.edu/
   7. http://www.aura-astronomy.org/
   8. https://science.jpl.nasa.gov/people/Sahai/
   9. http://www.jpl.nasa.gov/
  10. https://science.nasa.gov/missions/hubble/hubbles-spirograph/
  11. http://www.wordsmith.org/~anu/java/spirograph.html
  12. https://en.wikipedia.org/wiki/Planetary_nebula
  13. http://en.wikipedia.org/wiki/Spirograph
  14. https://en.wikipedia.org/wiki/Stellar_wind
  15. https://ui.adsabs.harvard.edu/abs/1997A&A...320..125H/abstract
  16. http://observing.skyhound.com/archives/jan/IC_418.html
  17. https://science.nasa.gov/sun/
  18. http://en.wikipedia.org/wiki/IC_418
  19. http://www.historyoftheuniverse.com/starold.html
  20. https://www.youtube.com/watch?v=7E-0j90Cwpk
  21. https://apod.nasa.gov/apod/ap100221.html
  22. https://apod.nasa.gov/apod/ap000910.html
  23. http://www.pbs.org/wgbh/aso/tryit/atom/
  24. https://apod.nasa.gov/apod/planetary_nebulae.html
  25. https://ui.adsabs.harvard.edu/abs/2009A&A...507.1517M/abstract
  26. https://spaceplace.nasa.gov/light-year/en/
  27. https://science.nasa.gov/asset/hubble/the-spirograph-nebula-ic-418/
  28. https://www.stsci.edu/hst
  29. https://www.reddit.com/r/cats/comments/8smej7/surprised_cat/#lightbox
  30. https://apod.nasa.gov/apod/ap250426.html
  31. https://apod.nasa.gov/apod/archivepix.html
  32. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  33. https://apod.nasa.gov/apod/lib/aptree.html
  34. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  35. https://apod.nasa.gov/apod/calendar/allyears.html
  36. https://apod.com/feed.rss
  37. https://apod.nasa.gov/apod/lib/edlinks.html
  38. https://apod.nasa.gov/apod/lib/about_apod.html
  39. https://asterisk.apod.com/discuss_apod.php?date=250427
  40. https://apod.nasa.gov/apod/ap250428.html
  41. http://www.phy.mtu.edu/faculty/Nemiroff.html
  42. http://www.phy.mtu.edu/
  43. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  44. http://www.astro.umd.edu/
  45. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  46. https://www.nasa.gov/about/highlights/HP_Privacy.html
  47. https://www.nasa.gov/general/accessibility/
  48. https://www.nasa.gov/privacy/
  49. https://astrophysics.gsfc.nasa.gov/
  50. https://www.nasa.gov/
  51. https://www.nasa.gov/centers/goddard/
  52. https://science.nasa.gov/learners
  53. http://www.mtu.edu/