长期共振迁移对经典Kuiper带的影响  

The Effect of Secular Resonance Sweeping in the Classical Kuiper Belt

作　　者：黎健[1] 周礼勇[1] 孙义燧[1] 

机构地区：[1]南京大学天文系,南京210093

出　　处：《天文学报》2008年第2期179-191,共13页Acta Astronomica Sinica

基　　金：国家自然科学基金(10233020;10403004);国家"973"项目(G200077303);教育部博士点基金(20020284011)资助项目

摘　　要：太阳星云气体的耗散可以引起长期共振迁移（secular resonance sweeping，SRS），当长期共振的位置扫过经典Kuiper带小天体（Kuiper Belt objects，KBOs），就会激发其轨道倾角．详细研究了在太阳系紧致构形中（指四个大行星轨道彼此相距较小的状态）SRS对经典KBOs轨道倾角的激发过程，发现KBOs轨道倾角受激发的程度敏感地依赖于星云气体中面与太阳系不变平面^1 的夹角δ：当星云气体中面与不变平面重合，即δ=0时，经典KBOs倾角受到的激发很小；而当星云气体中面与黄道面重合，即δ≈1．6^。时，在合理的初始条件下，经典KBOs的倾角最高可以被激发到30^。以上,另外，通过模拟木星具有较大轨道倾角的情形以及SRS和大行星轨道迁移同时发生的情形，发现对于经典KBOs倾角的受激发程度而言，它们两者的影响都远弱于6．The Kuiper Belt is a disk of small icy objects orbiting the Sun beyond Nep- tune, and the region between 40-48 AU in the Kuiper Belt is supposed to consist of ‘cold＇ objects on low inclination orbits, which is called the classical Kuiper Belt. But recently, observations show that a ‘hot＇ population whose inclinations can be as large as 30^. reside in this classical Kuiper Belt, and the secular resonance sweeping mechanism is a probable explanation： the residual solar nebula gas dispersal can cause secular resonance sweeping （SRS）, when the location of a secular resonance crosses the classical Kuiper Belt, the inclinations of the classical Kuiper Belt objects （KBOs） can be pumped up. The inclination excitation due to SRS has been investigated in detail in the compact configuration of the solar system （the orbits of four giant planets are closer to each other）. It is shown that the inclination excitation depends sensitively on the angle δ between the midplane of nebula gas and the invariable plane of solar system. If the midplane of nebula gas is coplanar with the invariable plane, i.e., δ=0, the inclination excitation is very small. But if the midplane of nebula gas is placed in the ecliptic plane, i.e., δ≈1.6^., the inclinations of the classical KBOs can attain values above 30^., as long as the residual nebula gas＇s density is about 1% of the minimum mass nebula model and the dissipation timescale is around 1.7 × 107 years （e.g. T Tauri stars）. Besides, by simulating the cases of more inclined Jupiter with respect to the invariable plane, and SRS along with the migration of giant planets, we show that the effects of both cases are much less than δ for exciting the inclinations of the classical KBOs.

关 键 词：方法 数值 Kuiper带 天体力学 太阳系 形成 

分 类 号：P134[天文地球—天体力学]