A Search for the Secular Resonances in the Dynamics of the Numbered Asteroids Passing through the Earth’s Gravity Sphere in the Nearest 200 Years

Abstract

The paper presents the results of studying the dynamics of the numbered near-Earth asteroids (NEAs) passing through the Earth’s gravity sphere (256000 km from the geocenter) in the nearest 200 years. The main goal of the study was to reveal secular resonances and investigate the mutual influence of the resonance relations and close encounters. For the NEAs in question, the orbital evolution in the time interval of 400 years was plotted and encounters of the asteroids with the large planets were revealed. Since the dynamics of these asteroids are predictable only in short time intervals, and the chaos in the NEA motion can be caused not only by close and/or repeated encounters with the large planets, but also by the presence of at least one unstable resonance, we traced the secular resonance dynamics of the NEAs. The degree of chaos of the NEA orbits was estimated by analyzing the behavior of the MEGNO parameter (Mean Exponential Growth factor of Nearby Orbits). It turned out that from the point of view of the search for secular resonances, the situation is similar for all the NEAs under study (99942 Apophis, 153201 2000 WO107, 153814 2001 WN5, and 456938 2007 YV56). All discovered resonances are stable; the chaos in the asteroids’ motion is caused by their close and/or repeated encounters with the large planets.