标题： 我们对外行星轨道了解多少？ 显示英文标题

标题： How Well Do We Know the Orbits of the Outer Planets?

摘要： 本文研究了外行星轨道参数的天文测量确定问题，特别是通过评估天文学观测检测由先锋效应或其他小引力扰动所预期的扰动的能力。 我们还表明，虽然使用简化的动力学模型可以提供一些见解，但必须小心避免过度简化相关问题，以免被分析误导到错误的方向。 具体而言，我们证明了目前冥王星的星历表并未排除存在先锋效应的可能性。 我们还表明，目前对冥王星轨道的描述还不足以做出这样的断言。 与这些主题相关的许多误解现在已经传播到文献中，并被用作推导太阳系动力学结论的基础。 因此，本文的目标是解决这些问题。 最后，我们对模型选择和比较这一复杂主题提出了一些评论。 显示英文摘要

摘要： This paper deals with the problem of astrometric determination of the orbital elements of the outer planets, in particular by assessing the ability of astrometric observations to detect perturbations of the sort expected from the Pioneer effect or other small perturbations to gravity. We also show that while using simplified models of the dynamics can lead to some insights, one must be careful to not over-simplify the issues involved lest one be misled by the analysis onto false paths. Specifically, we show that the current ephemeris of Pluto does not preclude the existence of the Pioneer effect. We show that the orbit of Pluto is simply not well enough characterized at present to make such an assertion. A number of misunderstandings related to these topics have now propagated through the literature and have been used as a basis for drawing conclusions about the dynamics of the solar system. Thus, the objective of this paper is to address these issues. Finally, we offer some comments dealing with the complex topic of model selection and comparison.