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Encyclopedia > Comets III


Credit : G. Borisov,Obs. of Naucsny/Institut Sternberg

Click here to see the animation of the motion of a comet.

To know how the names of comets are given, click here.

Comets are characterized by their particular morphology : 

-the core, center of the bright area, the size of which rarely exceeds 3 km and is made ​​of ice, snow and mixed rocks ;
-the tail or coma very bright around the core made ​​of water vapor and carbon dioxide enhanced by solar radiation ;
-a neutral hydrogen envelope a million kilometers around the comet ;
-the dust tail made of rock debris ejected with sublimated gas; it can reach 10 million kilometers long ;
-the ion tail made of plasmas interacting with the solar wind and may reach 100 millions kilometers long ;

- a highly eccentric orbit that regularly brings the comet in the vicinity of the Sun.

Opposite, the comet Hale-Bopp where we distinguish very well the blue ion tail and white dust tail. Many observations of this comet were made.