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.

                              2026 February 16
    [2]A star field shows colorful pill-shaped nebula extending from the
    bottom left toward the upper right. Colors include, from the outside
   in, red, green, and blue. Please see the explanation for more detailed
                                information.

                Unexplained Shocks Around a White Dwarf Star
     Image Credit: [3]ESO, [4]K. Iłkiewicz & [5]S. Scaringi [6]et al.;
    Text: [7]Cecilia Chirenti ([8]NASA [9]GSFC, [10]UMCP, [11]CRESST II)

   Explanation: How is RXJ0528+2838 creating such shock waves? A recently
   discovered [12]white dwarf star, the farther left of the two largest
   white spots, [13]RXJ0528+2838, was found 730 [14]light-years away from
   [15]Earth. Most stars, when [16]done fusing nuclei in their cores for
   energy, become [17]red giant stars, the cores of which [18]live on as
   faint dense [19]white dwarfs that slowly cool down for the rest of
   time. White dwarfs are so dense that the only thing that stops them
   from collapsing further is [20]quantum mechanics. In about 5 billion
   years, [21]our Sun will become a [22]white dwarf, too. The [23]featured
   image, obtained with the [24]European Southern Observatory’s [25]Very
   Large Telescope, shows unexplained [26]bow shocks around RXJ0528+2838,
   similar to the [27]bow wave of water around a fast-moving ship.
   Astronomers [28]don’t yet know what is powering [29]these shocks, which
   have existed for at least 1,000 years. The red, green and blue colors
   represent trace amounts of glowing [30]hydrogen, [31]nitrogen and
   [32]oxygen gas.

    Open Science: [33]Browse 3,900+ codes in the Astrophysics Source Code
                                   Library
                      Tomorrow's picture: passing comet
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    Authors & editors: [45]Robert Nemiroff ([46]MTU) & [47]Jerry Bonnell
                                 ([48]UMCP)
          NASA Official: Amber Straughn [49]Specific rights apply.
            [50]NASA Web Privacy, [51]Accessibility, [52]Notices;
                A service of: [53]ASD at [54]NASA / [55]GSFC,
                         [56]NASA Science Activation
                           & [57]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2602/WhiteDwarfShock_VLT_960.jpg
   3. https://www.eso.org/
   4. https://www.camk.edu.pl/en/staff/ilkiewicz/
   5. https://www.depts.ttu.edu/phas/People/Faculty/bio_scaringi/bio_scaringi.php
   6. https://www.eso.org/public/archives/releases/sciencepapers/eso2601/eso2601a.pdf
   7. https://science.gsfc.nasa.gov/sci/bio/cecilia.bertonimarthahadlerchirenti
   8. https://www.nasa.gov/
   9. https://www.nasa.gov/goddard/
  10. https://www.astro.umd.edu/people/cecilia-chirenti
  11. https://cresst2.umd.edu/
  12. https://science.nasa.gov/universe/stars/types/#white-dwarfs
  13. https://www.science.org/content/article/scientists-spot-never-seen-shock-wave-around-dead-star
  14. https://spaceplace.nasa.gov/light-year/
  15. https://apod.nasa.gov/apod/ap170709.html
  16. https://science.nasa.gov/universe/stars/#death
  17. https://en.wikipedia.org/wiki/Red_giant
  18. https://apod.nasa.gov/apod/ap260123.html
  19. https://en.wikipedia.org/wiki/White_dwarf
  20. https://en.wikipedia.org/wiki/Quantum_mechanics
  21. https://apod.nasa.gov/apod/ap260208.html
  22. https://apod.nasa.gov/apod/ap231224.html
  23. https://www.eso.org/public/images/eso2601b/
  24. https://www.eso.org/public/about-eso/
  25. https://www.eso.org/public/teles-instr/paranal-observatory/vlt/
  26. https://science.nasa.gov/science-research/astrophysics/cosmic-bow-shocks/
  27. https://www.britannica.com/science/bow-wave
  28. https://media.istockphoto.com/id/509119713/photo/weimaraner-with-head-cocked.jpg?s=612x612&w=0&k=20&c=FMXNT4yye2_I5n5Z8ZGJZxlYnosXXw9xPcUQ1FtATdM="
  29. https://www.nature.com/articles/s41550-025-02748-8
  30. https://astrobiology.nasa.gov/news/deep-hydrogen/
  31. https://periodic.lanl.gov/7.shtml
  32. https://science.nasa.gov/universe/exoplanets/oxygen-on-exoplanets-isnt-proof-of-life/
  33. https://ascl.net/code/all
  34. https://apod.nasa.gov/apod/ap260215.html
  35. https://apod.nasa.gov/apod/archivepix.html
  36. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  37. https://apod.nasa.gov/apod/lib/aptree.html
  38. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  39. https://apod.nasa.gov/apod/calendar/allyears.html
  40. https://apod.com/feed.rss
  41. https://apod.nasa.gov/apod/lib/edlinks.html
  42. https://apod.nasa.gov/apod/lib/about_apod.html
  43. https://asterisk.apod.com/discuss_apod.php?date=260216
  44. https://apod.nasa.gov/apod/ap260217.html
  45. http://www.phy.mtu.edu/faculty/Nemiroff.html
  46. http://www.phy.mtu.edu/
  47. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  48. http://www.astro.umd.edu/
  49. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  50. https://www.nasa.gov/about/highlights/HP_Privacy.html
  51. https://www.nasa.gov/general/accessibility/
  52. https://www.nasa.gov/privacy/
  53. https://astrophysics.gsfc.nasa.gov/
  54. https://www.nasa.gov/
  55. https://www.nasa.gov/centers/goddard/
  56. https://science.nasa.gov/learners
  57. http://www.mtu.edu/