Migration of Trans-Neptunian Objects to the Terrestrial Planets

The orbital evolution of more than 22000 Jupiter-crossing objects under thegravitational influence of planets was investigated. We found that the meancollision probabilities of Jupiter-crossing objects (from initial orbits close tothe orbit of a comet) with the terrestrial planets can differ by more than twoorders of magnitude for different comets. For initial orbital elements close tothose of some comets (e.g., 2P and 10P), about 0.1% of objects got Earth-crossingorbits with semi-major axes a < 2 AU and moved in such orbits for more than a Myr (up to tens or even hundreds of Myrs).Results of our runs testify in favor of at least one of these conclusions: (1) the portionof 1-km former trans-Neptunian objects (TNOs) among near-Earth objects (NEOs)can exceed several tens of percent, (2) the number of TNOs migrating inside the solarsystem could be smaller by a factor of several than it was earlier considered, (3) mostof 1-km former TNOs that had got NEO orbits disintegrated into mini-comets and dustduring a smaller part of their dynamical lifetimes if these lifetimes are not small.