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.

                                2022 June 26
    [2]The featured image shows the unusual light echo structure known as
       V838 Mon. The illuminated dust is patchy and surrounds a bright
       red-colored star. Please see the explanation for more detailed
                                information.

                         Light Echoes from V838 Mon
           Image Credit: [3]NASA, [4]ESA, [5]H. E. Bond ([6]STScI)

   Explanation: What caused this outburst of V838 Mon? For reasons
   unknown, star [7]V838 Mon's outer surface [8]suddenly greatly expanded
   with the result that it became one of the [9]brighter stars in the
   [10]Milky Way Galaxy in early 2002. Then, just as suddenly, [11]it
   shrunk and faded. A [12]stellar flash like this had never been seen
   before -- [13]supernovas and [14]novas expel matter out into space.
   Although the [15]V838 Mon flash appears to expel material into space,
   what is seen in the [16]featured image from the [17]Hubble Space
   Telescope is actually an outwardly expanding [18]light echo of the
   original flash. In a [19]light echo, light from the flash is reflected
   by successively [20]more distant surfaces in the complex array of
   ambient [21]interstellar dust that already surrounded the star.
   [22]V838 Mon lies about 20,000 [23]light years away toward the
   [24]constellation of the unicorn ([25]Monoceros), while the [26]light
   echo above spans about six [27]light years in diameter.

                  Tomorrow's picture: gummy mountain stars
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    Authors & editors: [39]Robert Nemiroff ([40]MTU) & [41]Jerry Bonnell
                                 ([42]UMCP)
          NASA Official: Phillip Newman [43]Specific rights apply.
              [44]NASA Web Privacy Policy and Important Notices
                A service of: [45]ASD at [46]NASA / [47]GSFC
                           & [48]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2206/V838Mon_Hubble_2238.jpg
   3. https://www.nasa.gov/
   4. https://esahubble.org/
   5. https://www.stsci.edu/~bond/
   6. https://www.stsci.edu/
   7. https://en.wikipedia.org/wiki/V838_Monocerotis
   8. https://media.istockphoto.com/photos/curious-cat-face-peeps-out-picture-id1202689418?k=20&m=1202689418&s=612x612&w=0&h=xOIn_9jq1icnUcpdr6-G8n9RRQHZA5f9X5UcGBQ3z_0=
   9. https://en.wikipedia.org/wiki/List_of_most_luminous_stars
  10. https://solarsystem.nasa.gov/resources/285/the-milky-way-galaxy/
  11. https://ui.adsabs.harvard.edu/abs/2005A&A...436.1009T/abstract
  12. https://www.aanda.org/articles/aa/full_html/2014/09/aa24458-14/aa24458-14.html
  13. https://heasarc.gsfc.nasa.gov/docs/snr.html
  14. https://youtu.be/zYmd8EETy74
  15. https://apod.nasa.gov/apod/ap140617.html
  16. https://hubblesite.org/contents/media/images/3867-Image
  17. https://apod.nasa.gov/apod/ap010806.html
  18. https://apod.nasa.gov/apod/ap971023.html
  19. https://en.wikipedia.org/wiki/Light_echo
  20. https://viewspace.org/interactives/unveiling_invisible_universe/variable_stars/v838_monocerotis
  21. https://apod.nasa.gov/apod/ap990509.html
  22. https://slate.com/technology/2013/12/when-stars-collide-the-enigmatic-beauty-of-v838-mon.html
  23. https://chandra.harvard.edu/photo/cosmic_distance.html
  24. https://apod.nasa.gov/apod/ap030401.html
  25. https://en.wikipedia.org/wiki/Monoceros
  26. http://www.aavso.org/vsots_v838mon
  27. https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html
  28. https://apod.nasa.gov/apod/ap220625.html
  29. https://apod.nasa.gov/apod/archivepix.html
  30. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  31. https://apod.nasa.gov/apod/lib/aptree.html
  32. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  33. https://apod.nasa.gov/apod/calendar/allyears.html
  34. https://apod.nasa.gov/apod.rss
  35. https://apod.nasa.gov/apod/lib/edlinks.html
  36. https://apod.nasa.gov/apod/lib/about_apod.html
  37. http://asterisk.apod.com/discuss_apod.php?date=220626
  38. https://apod.nasa.gov/apod/ap220627.html
  39. http://www.phy.mtu.edu/faculty/Nemiroff.html
  40. http://www.phy.mtu.edu/
  41. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  42. http://www.astro.umd.edu/
  43. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  44. https://www.nasa.gov/about/highlights/HP_Privacy.html
  45. https://astrophysics.gsfc.nasa.gov/
  46. https://www.nasa.gov/
  47. https://www.nasa.gov/centers/goddard/
  48. http://www.mtu.edu/