                        Astronomy Picture of the Day

    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 January 4

                           Zeta Oph: Runaway Star
          Image Credit: NASA, JPL-Caltech, Spitzer Space Telescope

   Explanation: Like a ship plowing through cosmic seas, runaway star Zeta
   Ophiuchi produces the arcing interstellar bow wave or bow shock seen in
   this stunning infrared portrait. In the false-color view, bluish Zeta
   Oph, a star about 20 times more massive than the Sun, lies near the
   center of the frame, moving toward the left at 24 kilometers per
   second. Its strong stellar wind precedes it, compressing and heating
   the dusty interstellar material and shaping the curved shock front.
   What set this star in motion? Zeta Oph was likely once a member of a
   binary star system, its companion star was more massive and hence
   shorter lived. When the companion exploded as a supernova
   catastrophically losing mass, Zeta Oph was flung out of the system.
   About 460 light-years away, Zeta Oph is 65,000 times more luminous than
   the Sun and would be one of the brighter stars in the sky if it weren't
   surrounded by obscuring dust. The image spans about 1.5 degrees or 12
   light-years at the estimated distance of Zeta Ophiuchi. In January
   2020, NASA placed the Spitzer Space Telescope in safe mode, ending its
   16 successful years of exploring the cosmos.

                  Tomorrow's picture: at the heart of Orion
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                           NASA Science Activation
                             & Michigan Tech. U.

