Peculiarities of the motion of asteroid 99942 Apophis

Impact trajectories of the asteroid Apophis in the 21st century

“…IMPACT TRAJECTORIES In many cases, the accuracy is insufficient to carry out direct numerical integration with the current ini tial data and thus search for Apophis' hazardous tra jectories with encounters after 2036 (Bykova, and Galushina, 2008;Sokolov et al, 2008a). The reason is the scattering of potential trajectories after the 2029 and 2036 Earth approaches.…”

“…In the calculations we used the following integrator parameters: NOR = 15, LL = 10, and NI = 2. In our previous paper (Sokolov et al, 2008a), we also used the DE403 ephemeris (Standish, 1995).…”

“…The number of identified encoun ters was significantly greater than that of collisions, as in (Yeomans et al, 2009). Most of these encounters can be identified by using the zero radius SOI method, as illustrated in Table 8 in (Sokolov et al, 2008a).…”

“…The search for the data in the new area no longer poses a fundamental difficulty. The generating quasi random solutions (Alekseev, 2001) composed of resonant impact orbits found by the zero radius sphere of influence (SOI) method are very useful both for a qualitative description of a large number of hazardous trajectories and as an initial approximation (Sokolov et al, 2008a).…”

“…The accuracy of its orbit is analyzed, in particular, in the works of Russian authors (Yagudin and Shor, 2005, Vinogradova et al, 2008Kochetova et al, 2009;Shor et al, 2012). The research on the possible strategies for deflecting the asteroid's orbit shows that deflection efforts may be effective only if they are made well in advance of the 2029 approach (see, e.g., Sokolov et al, 2008a). However, in April 2036 there is the possibility of not only a col lision, but simply a close encounter of Apophis with the Earth.…”