CHAOTIC CAPTURE OF NEPTUNE TROJANS
CHAOTIC CAPTURE OF NEPTUNE TROJANS
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DOI：
10.1088/0004-6256/137/6/5003
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发表时间：
2009-05
期刊：
影响因子：
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通讯作者：
D. Nesvorný;D. Vokrouhlický
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文献类型：
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作者：
D. Nesvorný;D. Vokrouhlický
海王星特洛伊（Neptune Trojans，NT）是一群太阳系外的天体，在海王星围绕太阳旋转的过程中引导/跟踪海王星。观测结果表明，NT形成了一个厚厚的天体云，其数量可能是木星特洛伊的10倍，轨道倾角达到25°。NT的高倾角指示捕获而不是原位形成。在这里，我们研究了一个模型，在该模型中，NTs被捕获海王星在行星迁移时，二次共振与天王星和海王星之间的平均运动可伸缩性扫过海王星的拉格朗日点。这个过程被称为混沌捕获，类似于先前提出的解释木星特洛伊人起源的方法。我们表明，从一个1035地球质量的微行星盘的微行星的混沌捕获可以产生一个人口的NT，至少是可比的数量从目前的观测推断。NTs的大轨道倾角是混沌捕获的自然结果。要获得观测所建议的高倾角和低倾角星群之间的1.44：1的比例，可能需要行星迁移到动力激发的星子盘中。所需的搅拌可能是由在盘中形成的冥王星大小和更大的物体引起的。
Neptune Trojans (NTs) are swarms of outer solar system objects that lead/trail planet Neptune during its revolutions around the Sun. Observations indicate that NTs form a thick cloud of objects with a population perhaps ∼10 times more numerous than that of Jupiter Trojans and orbital inclinations reaching ∼25°. The high inclinations of NTs are indicative of capture instead of in situ formation. Here we study a model in which NTs were captured by Neptune during planetary migration when secondary resonances associated with the mean-motion commensurabilities between Uranus and Neptune swept over Neptune's Lagrangian points. This process, known as chaotic capture, is similar to that previously proposed to explain the origin of Jupiter's Trojans. We show that chaotic capture of planetesimals from an ≈35 Earth-mass planetesimal disk can produce a population of NTs that is at least comparable in number to that inferred from current observations. The large orbital inclinations of NTs are a natural outcome of chaotic capture. To obtain the ∼4:1 ratio between high- and low-inclination populations suggested by observations, planetary migration into a dynamically excited planetesimal disk may be required. The required stirring could have been induced by Pluto-sized and larger objects that have formed in the disk.