Abstract

We consider some aspects of the dynamic evolution of the population of near-Earth asteroids (NEAs): the change of the rate of NEA depletion with time, including the dependence of the rate on the initial parameters of the NEA orbits, the efficiency of various channels of NEA depletion, and diffusion of NEA orbits. We studied both real asteroids and a simulated population. For the study, 3024 real asteroids larger than 1 km with a perihelion distance \(q < 1.6\) A.U. were selected, of which 833 NEAs had \(q < 1.3\), i.e., we explored almost all large NEAs. For some tasks, the population of NEAs was also modeled using NEOPOP (ESA) code. The orbits were integrated for 10 Myr using the REBOUND numerical complex. The solar gravitational field and field of planets, as well as the possibility of collisions, were considered. It is shown that the total population of NEAs has the median time of depletion \({{t}_{{{\text{NEA}}}}} \simeq 3.5\) Myr; this rectifies the estimates of other authors. The main advantage of the present study is that, for the first time, the dependence on the initial values ​​of the orbital parameters—semi-major axis of the orbit and eccentricity was investigated. It is shown that this dependence is very strong: for the subset of asteroids with large \(a\) and \(e\), \({{t}_{{{\text{NEA}}}}}\) it is dozens of times lower than for the subset with small \(a\) and \(e\). Obtained qualitative estimates of the dependence \({{t}_{{{\text{NEA}}}}}(a,\;e)\) are important for the quantitative analysis regarding the various model adequacy of mechanisms of replenishing the population of NEAs. The details of the diffusion (mixing of parameters) of the asteroid orbits in the plane “a–e” in the process of evolution have been studied. During the integration time, 10% of the NEAs were ejected from the Solar System, 1.5% fell onto the planets (including 0.2% onto the Earth), 17% fell onto the Sun, and 12.5% ​​left the NEAs zone.

中文翻译：

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关于近地小行星种群的动态演化

摘要

我们考虑近地小行星 (NEA) 种群动态演化的一些方面：NEA 消耗速率随时间的变化，包括速率对 NEA 轨道初始参数的依赖性、各种效率NEA 耗尽和 NEA 轨道扩散的通道。我们研究了真实的小行星和模拟的人口。本研究选择了3024颗大于1公里、近日点距离\(q < 1.6\) AU的真实小行星，其中833颗NEA具有\(q < 1.3\)，即，我们探索了几乎所有大型 NEA。对于某些任务，还使用 ​​NEOPOP (ESA) 代码对 NEA 的总体进行建模。使用 REBOUND 数值复数对 10 Myr 的轨道进行积分。考虑了太阳引力场和行星场，以及碰撞的可能性。结果表明，NEA 的总人口具有消耗的中值时间\({{t}_{{{\text{NEA}}}}} \simeq 3.5\) Myr；这纠正了其他作者的估计。本研究的主要优点是，首次研究了轨道参数-轨道半长轴和偏心率对初始值的依赖性。表明这种依赖性非常强：对于具有大\(a\)和\(e\)的小行星子集, \({{t}_{{{\text{NEA}}}}}\)它比具有小\(a\)和\(e\)的子集低几十倍。获得的依赖性\({{t}_{{{\text{NEA}}}}}(a,\;e)\) 的定性估计对于关于补充机制的各种模型充分性的定量分析很重要。 NEA 的人口。已经研究了演化过程中小行星轨道在“ a-e ”平面内扩散（参数混合）的细节。在积分时间内，10%的NEAs从太阳系中弹出，1.5%落到行星上（其中0.2%落到地球上），17%落到太阳上，12.5%离开了NEAs区。