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Ring-satellite interactions and orbital evolution in the Saturn system

土星系统中环-卫星相互作用和轨道演化

基本信息

批准号：
ST/I001581/1
负责人：
Carl Murray
金额：
$ 45.12万
依托单位：
Queen Mary University of London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2011
资助国家：
英国
起止时间：
2011 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=ST%2FI001581%2F1
关键词：
Ring satellite interactions orbital evolution

项目摘要

Saturn has the most spectacular and, thanks to the Cassini spacecraft, the most studied rings in the solar system. The results to date from Cassini show a ring system that is continually evolving under a variety of processes ranging from subtle gravitational interactions with perturbing moons, to impacts at several tens of metres per second between parts of the rings and moonlets which may be formed in the rings themselves. As the closest astrophysical disk to Earth, Saturn's rings represent a unique laboratory in which to study the same processes (but with different starting conditions) that give rise to planets. The ready availability of Cassini data combined with a basic understanding of how rings and moons form and evolve has revolutionised the study of planetary rings. Fundamental questions about the lifetime and evolution of the ring system of Saturn can be answered by understanding the processes by which ring material accumulates into moonlets and how small moons gravitationally interact with the rings. The proposed research will study the mechanisms by which gravitational instability in a ring can be induced by a passing moon using the narrow F ring and its shepherding moon, Prometheus, as a paradigm. We believe that there is evidence in the Cassini images of a process by which moonlets can form and evolve on timescales of months to years. Furthermore, we can model this process in numerical simulations and test our results by comparison with the actual rings and accompanying moonlets seen in the Cassini data. There is already evidence that embedded moonlets in Saturn's A ring are undergoing slow changes in their orbits under the gravitational effect of adjacent ring material and this is just one aspect of a more general problem relating to the lifetime of Saturn's rings: The current best estimate of the lifetime of the rings suggests that expanding satellite orbits and contracting ring orbits will mean that the rings can only survive for ~400My, which is <10% of the age of the solar system. Using orbital data extracted from long-term monitoring of satellites with Cassini images we intend to quantify this effect. We will also be investigating a possible means of 'locking' the ring system so that angular momentum is fed to a more massive, exterior satellite such as Mimas.

土星有着太阳系中最壮观的光环，多亏了卡西尼号航天器，它也是研究最多的光环。卡西尼号迄今为止的结果显示，一个环系统在各种过程中不断演变，从与扰动卫星的微妙引力相互作用，到环的部分和可能在环本身形成的小卫星之间每秒数十米的撞击。作为最接近地球的天体物理盘，土星环代表了一个独特的实验室，在其中研究产生行星的相同过程（但具有不同的起始条件）。卡西尼号数据的可用性与对环和卫星如何形成和演变的基本理解相结合，彻底改变了行星环的研究。关于土星环系统的寿命和演化的基本问题可以通过了解环材料积累成小卫星的过程以及小卫星如何与环相互作用来回答。拟议的研究将研究环中的引力不稳定性可以通过使用狭窄的F环及其牧羊卫星普罗米修斯作为范例的经过月球引起的机制。我们相信，卡西尼号的图像中有证据表明，小卫星可以在几个月到几年的时间尺度上形成和演变。此外，我们可以在数值模拟中模拟这一过程，并通过与卡西尼数据中看到的实际环和伴随的小卫星进行比较来测试我们的结果。已经有证据表明，嵌入土星A环的小卫星在邻近环物质的引力作用下正在经历轨道的缓慢变化，这只是与土星环寿命有关的更普遍问题的一个方面：目前对环寿命的最佳估计表明，扩张的卫星轨道和收缩的环轨道将意味着环只能存活~ 400 My，小于太阳系年龄的10%。我们打算利用从卡西尼号图像卫星长期监测中提取的轨道数据来量化这种影响。我们还将研究一种可能的方法来“锁定”环系统，以便角动量被馈送到一个更大的外部卫星，如土卫一。

项目成果

期刊论文数量（3）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

The structure of Saturn's F ring

土星F环的结构

DOI：
发表时间：
2012
期刊：
EGU General Assembly 2012
影响因子：
0
作者：
Murray Carl
通讯作者：
Murray Carl

Observations of Ejecta Clouds Produced by Impacts onto Saturn’s Rings

对土星环撞击产生的喷射云的观测

DOI：
10.1126/science.1233524
发表时间：
2013
期刊：
Science
影响因子：
56.9
作者：
M. Tiscareno;Colin J. Mitchell;Carl D. Murray;Daiana Di Nino;M. Hedman;Jürgen Schmidt;Joseph A. Burns;J. Cuzzi;C. Porco;K. Beurle;M. Evans
通讯作者：
M. Evans

The morphology of Saturn's F ring

土星F环的形态