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.

                               2019 October 25

                          The Ghosts of Cassiopeia
                  Image Credit & Copyright: Tommaso Stella

   Explanation: These bright rims and flowing shapes look ghostly on a
   cosmic scale. A telescopic view toward the constellation Cassiopeia,
   the colorful skyscape features swept-back, comet-shaped clouds IC 59
   (left) and IC 63. About 600 light-years distant, the clouds aren't
   actually ghosts. They are slowly disappearing though, under the
   influence of energetic radiation from hot,luminous star gamma Cas.
   Gamma Cas is physically located only 3 to 4 light-years from the
   nebulae, the bright star just above and left in the frame. Slightly
   closer to gamma Cas, IC 63 is dominated by red H-alpha light emitted as
   hydrogen atoms ionized by the star's ultraviolet radiation recombine
   with electrons. Farther from the star, IC 59 shows proportionally less
   H-alpha emission but more of the characteristic blue tint of dust
   reflected star light. The field of view spans over 1 degree or 10
   light-years at the estimated distance of gamma Cas and friends.

                     Tomorrow's picture: only the smile
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