The Yarkovsky Effect, Asteroid Dynamics and Impact Monitoring

This thesis is a collection of the work carried out during the three years of Ph.D. studies at the University of Pisa with the Celestial Mechanics Groups. The main topics of this thesis range from nongravitational perturbations, to asteroid orbit determination, and to the impact monitoring. The nongravitational perturbations arise because outer space is not empty, and they can affect not only the dynamics of Near Earth Asteroids (NEAs), but also the determination of the age of asteroid families. The main nongravitational perturbation is the Yarkovsky effect, a subtle nongravitational phenomenon related to the anisotropic thermal emission of Solar System objects. The nongravitational perturbations also affect the impact probabilities of NEAs, especially over long time span. For some special cases, we need to model the Yarkovsky effect to compute the long term propagation to the possible impacts and the intervening planetary encounters of NEAs.