文档介绍：Advances in Space Research 33 (2004) 1524–1533
ate/asr
Comet and asteroid hazard to the terrestrial s
. Ipatov a,b,*, . Mather c
a NASA/GSFC, Mail Code 685, Greenbelt, MD 20771, USA
b Institute of Applied Mathematics, Miusskaya sq. 4, Moscow 125047, Russia
c NASA/GSFC, Mail Code 685, Greenbelt, MD 20771, USA
Received 28 November 2002; received in revised form 7 April 2003; accepted 10 April 2003
Abstract
We estimated the rate et and asteroid collisions with the terrestrial s by calculating the orbits of 13,000 Jupiter-
crossing objects (JCOs) and 1300 resonant asteroids puting the probabilities of collisions based on random-phase ap-
proximations and the orbital elements sampled with a 500 years step. The Bulirsh–Stoer and a symplectic orbit integrator gave
similar results for orbital evolution, but may give different collision probabilities with the Sun. A small fraction of former JCOs
reached orbits with aphelia inside JupiterÕs orbit and some reached Apollo orbits with semi-major axes less than 2 AU, Aten orbits
and inner-Earth orbits (with aphelia less than AU) and remained there for millions of years. Though less than % of the
total, these objects were responsible for most of the collision probability of former JCOs with Earth and Venus. We conclude that a
significant fraction of near-Earth objects could be ets that came from the trans-