Analytical representation for ephemeris with short time spans:Application to the longitude of Titan
Analytical representation for ephemeris with short time spans:Application to the longitude of Titan
复制标题
短时间跨度星历的解析表示：在土卫六经度上的应用
DOI：
10.1051/0004-6361/201937148
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发表时间：
2020
影响因子：
6.5
通讯作者：
A.Vienne
中科院分区：
文献类型：
--
作者：
X.J.Xi;A.Vienne
语境。数值积分所得的天然卫星星历表在有限的时间间隔内与最近的观测结果有很好的拟合精度。同时，像 Vienne 和 Duriez 的《土星卫星理论分析》（TASS）这样的合成星历通过基于适当频率组合的表示来详细描述动力系统。一些理论研究需要兼具这两种优点。例如，要研究土卫六的自转，需要知道其经度的表示形式。我们的目标是利用这两种类型的星历表，在数值积分星历的基础上重建具有适当频率的持久且高精度的星历。目的是用类似于解析式的公式来描述数值星历表。我们使用一万年来分析的塔斯社星历表中的轨道元素表示作为参考模板。我们仅通过数值和 TASS 星历表获得了 1000 多年的正确频率。最小二乘程序使我们能够在这个有限的间隔内获得轨道元素的分析表示。结果。我们从 JPL 1000 年来的星历中获得了土卫六平均经度的表示。对于几乎所有分量，相应的幅度和相位与 TASS 的相对项相似。我们的表示与 JPL 的泰坦平均经度在 1000 年来的最大差异不到 100 公里，标准差约为 26 公里。
Context. The ephemerides of natural satellites resulting from numerical integration have a very good precision on the fitting to recent.observations, in a limited interval. Meanwhile, synthetic ephemerides like the Théorie Analytique des Satellites de Saturne (TASS) by.Vienne and Duriez describe in detail the dynamical system by a representation based on the combinations of the proper frequencies..Some theoretical studies need to have both advantages. For example, to study the rotation of Titan, one needs to know the representation.of its longitude..Aims. We aim to use these two types of ephemerides in order to rebuild a long-lasting and high-precision ephemeris with proper.frequencies based on the numerical integration ephemeris. The aim is to describe the numerical ephemerides with formulas similar to.analytical ones..Methods. We used the representation of the orbital elements from the TASS ephemeris analysed over 10 000 years as a reference.template. We obtained the proper frequencies with both numerical and the TASS ephemeris over 1000 years only. A least-square.procedure allowed us to get the analytical representation of an orbital element in this limited interval..Results. We acquire the representation of the mean longitude of Titan from JPL ephemeris over 1000 years. For almost all components,.the corresponding amplitudes and phases are similar to the relative terms from TASS. The biggest dierence between our.representation and the mean longitude of Titan of JPL is less than 100 km over 1000 years, and the standard deviation is about 26 km.