The size of collision solutions in orbital elements space

In the framework of the analytical theory of close encounters, and under suitable assumptions, we compute the size of the region in orbital elements space containing collisions solutions. In the linearized approximation in the semimajor axis/eccentricity plane the collision region is the interior of an ellipse. Examples are given from past cases of Near Earth Asteroids having the possibility of impacting our planet.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html