#comet  (astronomy) a relatively small extraterrestrial body consisting of a frozen mass that travels around the sun in a highly elliptical orbit
  supertype:  extraterrestrial_object__estraterrestrial_body  a natural object existing outside the earth and outside the earth's atmosphere
  part:  coma  (astronomy) the luminous cloud of particles surrounding the frozen nucleus of a comet; forms as the comet approaches the sun and is warmed
  part:  nucleus.midpoint__nucleu  (astronomy) the center of the head of a comet; consists of small solid particles of ice and frozen gas that vaporizes on approaching the sun to form the coma and tail

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