LOCAL VARIABILITY IN THE ORBIT OF SATURN'S F RING
LOCAL VARIABILITY IN THE ORBIT OF SATURN'S F RING
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土星 F 环轨道的局部变化
DOI：
10.1088/0004-6256/145/6/161
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
G. Williams
中科院分区：
文献类型：
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作者：
N. Cooper;Carl D. Murray;G. Williams
我们使用卡西尼号航天器的成像科学子系统记录的图像对土星F环的轨道进行了分析。在2006年11月23日至2009年7月28日期间获得的10幅图像序列中，总共进行了9805次观测。每个多达240张图像的序列跨越F环的单个轨道，允许在这~ 3年的时间内对环轨道进行10次独立的高精度估计。该环被建模为一个倾斜均匀进动的椭圆。结果显示了轨道要素的变异性，例如，半长轴在140211.2±0.1 km和140232.9±0.4 km之间离散，拟合的周期锁定在使用整个三年观测跨度的组合拟合的值上。我们表明，观测到的各个环轨道估计之间的分散反映了被拟合的特定环段的不同过去历史，并且这些值在与附近的卫星普罗米修斯（Prometheus）的一次引力接触所期望的范围内分散。在组合拟合中，散点平均值显示出相对于Bosh等人和Albers等人的结果有一个小的系统偏差。我们认为这是普罗米修斯在分析中选择的图像序列中靠近环的结果。最后，我们注意到F环的副旋进率与普罗米修斯与F环之间的synodic周期之间具有密切的经验可通约性，使得nProm−nFring≈2，其中nProm和nFring是平均运动，并讨论了其含义。
We present an analysis of the orbit of Saturn's F ring using images recorded by the Imaging Science Subsystem of the Cassini spacecraft. A total of 9805 observations have been made from 10 image sequences obtained between 2006 November 23 and 2009 July 28. Each sequence of up to 240 images spans a single orbit of the F ring, allowing 10 independent high-precision estimates of the ring orbit to be made over this ∼3 year period. The ring has been modeled as an inclined uniformly precessing ellipse. The results show a variability in the orbital elements with, for example, the semi-major axis scattered between 140211.2 ± 0.1 km and 140232.9 ± 0.4 km and the fitted periapses locked to the value obtained from a combined fit using the entire three-year span of observations. We show that the observed scatter between the individual estimates of the ring orbit reflect the differing past histories of the particular segments of ring being fitted and that the values are scattered within the limits expected from a single gravitational encounter with the nearby moon, Prometheus. In the combined fit, the scatter averages out to reveal a small systematic bias with respect to the results of Bosh et al. and Albers et al. We believe this is a consequence of the proximity of Prometheus to the ring in the image sequences chosen for this analysis. Finally, we note a close empirical commensurability between the apsidal precession rate, , of the F ring and the synodic period between Prometheus and the F ring, such that nProm − nFring ≈ 2, where nProm and nFring are the mean motions, and discuss its implications.
土星 F 环中低速碰撞的检测
DOI：
10.1088/2041-8205/755/2/l27
发表时间：
2012
期刊：
The Astrophysical Journal
影响因子：
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作者：
Attree N
通讯作者：
Attree N