Eirik Mysen: The dynamics of globally active triaxial comets, with applications to asteroid rotation

It will be demonstrated how globally distributed outgassing activity on a triaxial comet nucleus bridges the gap between the intuitive Sekanina model, used for comet orbit solutions, and the physics of outgassing on a comet nucleus. In this activity and shape limit, it will be shown how a recoil force component which originates from a day-side restricted sublimation process, is necessary to describe the comet's rotational evolution. Modifications of the non-gravitational force cosines are suggested, with a fundamentally different interpretation than before. Applications to asteroid rotation yield that the ability of specular reflection, of solar photons on an asteroid's surface, to change the asteroid's rotation period and equatorial obliquity, is not dependent on the overall shape of the asteroid. The rotation state of an asteroid determines how it is slowly delivered to the Solar System orbit resonances in which it rapidly could become an Earth orbit crossing object.