Numerous Weak Resonances Drive Asteroids toward Terrestrial Planets Orbits
Numerous Weak Resonances Drive Asteroids toward Terrestrial Planets Orbits
复制标题
无数的弱共振驱动小行星飞向类地行星轨道
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
D. Nesvorný
中科院分区：
文献类型：
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作者：
A. Morbidelli;D. Nesvorný
系统地探讨了小行星带的混沌结构，首先只考虑了四个巨行星提供的扰动，然后还包括内行星的影响。我们发现，无论是内带（一个2.8 Au）大多是混乱的。在带的外部，混乱是由于与木星和三体共振，木星-土星-小行星的许多平均运动共振的存在。在内部带，混沌是由与火星的平均运动共振和三体共振（火星-木星-小行星）产生的。由于小行星带的混乱，小行星倾向于以离心率缓慢迁移。这种“混乱扩散”现象使内带的许多物体成为火星穿越者。从内带泄漏出来的小行星数量足够大，足以使穿越火星的小行星数量保持稳定状态，尽管后者的动力学寿命很短（1.25亿年）。我们推测，混乱的扩散可能大大侵蚀了小行星带的高偏心率部分，从而提供了负责早期太阳系后期重轰炸阶段的撞击物。
A systematic exploration of the chaotic structure of the asteroid belt is presented, first taking into account only the perturbations provided by the four giant planets and then including also the effects of the inner planets. We find that both the inner belt (a 2.8 AU) are mostly chaotic. In the outer part of the belt, chaos is due to the presence of numerous mean-motion resonances with Jupiter and three-body resonances, Jupiter–Saturn–asteroid. In the inner belt, chaos is generated by mean motion resonances with Mars and three-body resonances, Mars–Jupiter–asteroid. Due to the chaoticity of the belt, asteroids tend to slowly migrate in eccentricity. This phenomenon of “chaotic diffusion” allows many bodies in the inner belt to become Mars-crossers. The number of asteroids leaking out from the inner belt is large enough to keep the population of Mars-crossing asteroids in steady state, despite of the short dynamical lifetime of the latter (∼25 Myr). We speculate that chaotic diffusion could have substantially eroded the high-eccentricity part of the asteroid belt, thus providing the impactors responsible for the Late Heavy Bombardment phase of the early Solar System.