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coma




comet coma, nucleus and tail
A glowing envelope of gas and dust that surrounds a comet's nucleus when the comet comes within a few astronomical units of the Sun (although Chiron has been seen to develop a coma at 11 AU). At perihelion, the coma is typically about 100,000 km across, and shaped into a teardrop by the solar wind. Together, the coma and the nucleus form the comet's head.


Related category

   • COMETS