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.

土星具有最壮观的，并且由于卡西尼航天器，这是太阳系中研究最多的环。迄今为止，来自卡西尼（Cassini）的结果显示了一个环系，该环节在各种过程中持续发展，从与摄动卫星的微妙相互作用到在环本身可能形成的环和月球之间每秒几十米的影响。作为最接近地球的天体物理磁盘，土星环代表了一个独特的实验室，其中研究相同的过程（但有不同的起始条件）会引起行星。卡西尼数据的现成可用性结合了对环和卫星如何形成和进化的基本了解，彻底改变了行星环的研究。关于土星环系统的生命和演变的基本问题，可以通过了解环材料积聚成月球的过程以及小卫星与环的相互作用的过程来回答。拟议的研究将研究通过狭窄的f环及其牧羊月球Prometheus作为范式来诱导环中引力不稳定性的机制。我们认为，卡西尼图像中有证据表明月球可以在数月到几年的时间尺度上形成和发展的过程。此外，我们可以在数值模拟中对此过程进行建模，并通过与Cassini数据中看到的实际环和随附的月球进行比较来测试我们的结果。已经有证据表明，在土星的一圈中，嵌入的月球正在经历缓慢的变化，在相邻环材料的重力效果下，轨道变化缓慢，这只是与土星环的寿命相关的更一般问题的一个方面：当前的最佳估计值是，环的生命的最佳估计是，五个卫星和合同环的范围都可以延长iSrive for for for rising of for your to yourbits of to your to yourbits yourbits yourbits yourbits yourbits yourbits yourbits yourbits yourbits yourbits ring yourbits yourbits yourbits yourbits ring〜hort y〜太阳系的年龄。使用与Cassini图像对卫星的长期监测提取的轨道数据，我们打算量化这种效果。我们还将调查“锁定”环系统的可能手段，以便将角动量馈送到更大的外部卫星（例如Mimas）。