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.

                                2020 March 2

                      Sharpless-308: The Dolphin Nebula
    Image Credit & Copyright: Chilesope 2, Pleaides Astrophotography Team
                                 (Peking U.)

   Explanation: Blown by fast winds from a hot, massive star, this cosmic
   bubble is much larger than the dolphin it appears to be. Cataloged as
   Sharpless 2-308 it lies some 5,200 light-years away toward the
   constellation of the Big Dog (Canis Major) and covers slightly more of
   the sky than a Full Moon. That corresponds to a diameter of 60
   light-years at its estimated distance. The massive star that created
   the bubble, a Wolf-Rayet star, is the bright one near the center of the
   nebula. Wolf-Rayet stars have over 20 times the mass of the Sun and are
   thought to be in a brief, pre-supernova phase of massive star
   evolution. Fast winds from this Wolf-Rayet star create the
   bubble-shaped nebula as they sweep up slower moving material from an
   earlier phase of evolution. The windblown nebula has an age of about
   70,000 years. Relatively faint emission captured in the featured
   expansive image is dominated by the glow of ionized oxygen atoms mapped
   to a blue hue.

                     Tomorrow's picture: around the moon
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                             & Michigan Tech. U.

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