Tidal Processes in Planetary and Stellar Systems

地球上的潮汐每天都在经历，它们也广泛地出现在天界。在这里，我建议研究它们的两个表现形式。 火热的木星。第一批已知的太阳系外行星，以令人难以置信的近距离绕其恒星运行。它们通常被认为是动态迁移的产物：它们形成于比它们当前位置更远的地方，与它们的邻居(恒星或行星)的角动量交换可能会逐渐将它们原来的圆形轨道挤压成非常窄的椭圆；当它们被恒星周期性地摇摆时，这些行星上的强潮会被抬高。如果潮汐晃动能够消散成热量，行星轨道就会衰变，一颗炽热的木星就会诞生。这样的动力迁移理论，虽然巧妙地解释了热木星的许多观察到的特征，但也包含了一些主要的弱点--所有这些都与我们对潮汐过程缺乏了解有关。因此，为了确定热木星的起源，我建议对潮汐过程进行详细的研究。在这样的研究结束时，我们应该能够解释这些行星目前的轨道和大小。最终理解自然产生的这类奇异物体将是令人满意的。 另一种非常极端的潮汐过程发生在一颗小行星离大质量天体(行星或恒星)的表面非常近的时候。之前的遗体可以被粉碎成数百万个小碎片，其中一些逃脱了驱逐舰的引力，最终重新凝结成更大的块状物。我们认为，这种灾难性的事件可能是产生我们在恒星周围看到的许多明亮的尘埃盘，即所谓的碎片盘的原因。这与碎片盘形成的传统图景不同，在传统图景中，假设大量的小行星在早期无法并入行星，但留在后面，并在数十亿年后逐渐粉碎为尘埃。我建议研究潮汐破坏事件的细节，以预测可能引起的碎片盘的频率和外观。这样的工作也适用于我们太阳系中的柯伊伯带天体。

Tides are experienced daily here on Earth, they also occur widely in the celestial realm. Here, I propose to study two of their manifestations. Hot Jupiters. the first-known population of extra-solar planets, orbit their stars at implausibly close ranges. They are often suggested to be the products of dynamical migration: formed much further away than their current locations, angular momentum exchange with their neighbours (either stellar or planetary ones) may gradually squeeze their original round orbits into very narrow ellipses; strong tides are raised on these planets as they sway by their stars periodically. If the tidal sloshing can be dissipated into heat, the planet orbit will decay and a hot Jupiter is born. Such a theory of dynamical migration, while neatly explaining many of the observed features of hot Jupiters, contains a number of major weaknesses -- all related to our lack of understandings on the tidal process. So in order to firmly establish the origin of hot Jupiters, I propose to study the tidal process in detail. At the end of such a study, we should be able to explain the current orbits and sizes of these planets. It will be satisfying to finally understand this class of exotic objects that nature produces. Another very extreme tidal process occurs when a small planet passes very close from the surface of a massive body (a planet or a star). The former body can be shredded into millions of little debris, with some of them escaping the gravitational pull of the destroyer and eventually re-conglomerating into larger clumps. Such a catastrophic event, we propose, may be responsible for producing the many bright dusty disks we see around stars, the so-called debris disks. This breaks away from the conventional picture of debris disk formation, where it is hypothesized that quantities of planetesimals, unable to be incorporated into planets at early days, remain behind and gradually grind down to dust over billions of years. I propose to study the details of the tidal disruption event, in order to predict the frequency and the appearance of debris disks this can give rise to. Such a work also have applications for the Kuiper belt objects in our own solar system.