Oort spike comets with large perihelion distances
Oort spike comets with large perihelion distances
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DOI：
10.1093/mnras/stx2157
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发表时间：
2017-12-01
影响因子：
4.8
通讯作者：
Dybczynski, Piotr A.
中科院分区：
文献类型：
--
作者：
Krolikowska, Malgorzata;Dybczynski, Piotr A.
从确定它们的轨道开始，研究了1901-2010年间发现的大近日点近抛物线彗星的完整样本。接下来，研究了包括三次近日点通道（先前观察到的-下一次观察到的）的轨道演化，其中包含了星系扰动和经过恒星扰动的完整模型。我们表明，实际的大型近日点彗星在穿越太阳系时所遭受的行星扰动分布有一个深的、意想不到的在零附近的最小值，这表明缺乏“几乎不受扰动”的彗星。通过一系列的模拟，我们表明，这个深井对被分析彗星的轨道元素的一些扩散有一定的抵抗力。似乎有理由断言，观察到的这些大型近日点彗星流在通过行星带时经历了一系列特定的行星结构。对这些彗星过去的动态分析清楚地表明，只有当它们的原始半长轴大于20,000 au时，才会出现动态的新彗星。另一方面，对于长度超过40000 au的半长轴，动态年老的彗星是完全不存在的。我们证明了观测到的1/a(ori)-分布表现出一个局部最小值，将动态新彗星和动态老彗星分开。长期动力学研究揭示了各种各样的轨道行为。还描述了几个有趣的恒星经过的例子，特别是Gliese 710的影响，它将在未来接近太阳。然而，所获得的恒星扰动都不足以改变所分析彗星的动力学状态。
The complete sample of large-perihelion nearly-parabolic comets discovered during the period 1901-2010 is studied, starting with their orbit determination. Next, an orbital evolution that includes three perihelion passages (previous-observed-next) is investigated in which a full model of Galactic perturbations and perturbations from passing stars is incorporated. We show that the distribution of planetary perturbations suffered by actual large-perihelion comets during their passage through the Solar system has a deep, unexpected minimum around zero, which indicates a lack of 'almost unperturbed' comets. Using a series of simulations we show that this deep well is moderately resistant to some diffusion of the orbital elements of the analysed comets. It seems reasonable to assert that the observed stream of these large-perihelion comets experienced a series of specific planetary configurations when passing through the planetary zone. An analysis of the past dynamics of these comets clearly shows that dynamically new comets can appear only when their original semimajor axes are greater than 20 000 au. On the other hand, dynamically old comets are completely absent for semimajor axes longer than 40 000 au. We demonstrate that the observed 1/a(ori)-distribution exhibits a local minimum separating dynamically new from dynamically old comets. Long-term dynamical studies reveal a wide variety of orbital behaviour. Several interesting examples of the action of passing stars are also described, in particular the impact of Gliese 710, which will pass close to the Sun in the future. However, none of the obtained stellar perturbations is sufficient to change the dynamical status of the analysed comets.