Add comets

[aligusnet]

Comets can be considered as a special type of planets.

The things to be taken into account:

• large eccentricity of comets requires careful approach to solve Kepler's equation'
• comets can be considered as inner planet or outer planet depending on the distance to the Sun.

The list of comets to add is open. Should be added some of the most famous comets like Halley.