Planetary Impact Rates from Ecliptic Comets
Planetary Impact Rates from Ecliptic Comets
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DOI：
10.1006/icar.1999.6313
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发表时间：
2000-02
期刊：
影响因子：
3.2
通讯作者：
H. Levison;M. Duncan;K. Zahnle;M. Holman;L. Dones
中科院分区：
文献类型：
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作者：
H. Levison;M. Duncan;K. Zahnle;M. Holman;L. Dones
我们利用H. Levison和M. Duncan （1997, Icarus 127, 13-32; LD97）的综合数据重新评估了黄道彗星对行星的撞击率。我们发现，由于计算相关时间尺度的方法不同，目前对巨行星的撞击率实际上比LD97的值小四倍左右。然而，如果离开柯伊伯带的天体主要位于高倾角轨道上，那么对巨行星的撞击率将比表1中的撞击率大一个因子> 2。我们详细讨论了撞击巨行星的物体的动力学，包括撞击速度的测量。我们发现，在我们的模拟中，撞击木星的物体中有21%是在撞击前绑定在木星上的。土星的束缚撞击器的比例要低得多。木星、土星和天王星对于未受约束的撞击体具有显著的顶前不对称。
We have reevaluated the impact rates for the planets from ecliptic comets using the integrations in H. Levison and M. Duncan (1997, Icarus 127, 13–32; LD97). We find that the current impact rates on the giant planets are actually about four times smaller than LD97's values due to differences in methods of calculating the relevant timescales. The newly calculated impact rates are listed in Table I. However, if the objects leaving the Kuiper belt were primarily on high inclination orbits, then the impact rates on the giant planets are larger than those in Table I by a factor ≲2. We discuss the dynamics of objects hitting the giant planets in detail, including measurements of the impact velocities. We find that 21% of the objects that hit Jupiter in our simulations were bound to the planet before the impact. The fraction of bound impactors for Saturn is much lower. Jupiter, Saturn, and Uranus have a significant apex–antapex asymmetry for the unbound impactors.