Tidal Processes in Planetary and Stellar Systems

行星和恒星系统中的潮汐过程

• 批准号: RGPIN-2018-05886
• 负责人: Wu, Yanqin
• 金额: $ 5.97万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=743972
• 关键词: Tidal; Processes; Planetary; Stellar; Systems

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.

潮汐在地球上每天都在经历，它们也广泛地发生在天体领域。在这里，我建议研究他们的两种表现形式。这是第一批已知的太阳系外行星，它们以难以置信的近距离绕着恒星运行。它们通常被认为是动力迁移的产物：形成于比它们现在的位置更远的地方，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狭窄的椭圆形;当它们周期性地在它们的恒星附近摇摆时，这些行星上会产生强烈的潮汐。如果潮汐晃动可以消散成热量，行星轨道将衰减，一个热木星诞生。这样一个动力迁移理论，虽然巧妙地解释了许多观测到的热彗星的特征，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理解有关。因此，为了更好地确定热彗星的起源，我建议详细研究潮汐过程。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。最终了解这类大自然产生的奇异物体将是令人满意的。另一个非常极端的潮汐过程发生在一个小行星从一个大质量物体（行星或星星）的表面非常接近时。前一个身体可以被撕碎成数百万个小碎片，其中一些逃离了驱逐舰的引力，最终重新聚集成更大的团块。我们认为，这样的灾难性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的原因，即所谓的碎片盘。 这打破了碎片盘形成的传统图像，其中假设大量的星子，无法在早期并入行星，留在后面，并在数十亿年内逐渐研磨成尘埃。我建议研究潮汐破坏事件的细节，以预测碎片盘的频率和外观，这可能会引起。 这样的工作也可以应用于我们太阳系中的柯伊伯带天体。