Dynamical evolution of comets from high-eccentricity trans-Neptunian orbits to near-Earth space

The contribution of high-eccentricity trans-Neptunian objects to the observed populations of both short-period and long-period comets is estimated. About 10(10) objects with a radius R>0.7 km in orbits with perihelion distances 28<q<35.5 AU and semimajor axes 60<a<1000 AU are the main source of Jupiter-family comets. If the population of high-eccentricity trans-Neptunian objects formed about 4.5 Gyr ago, the mean near-parabolic flux produced by these objects is on the order of 0.3-1.0 AU(-1) yr(-1) for comets with R>0.7 km.