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: $ 2.99万
• 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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=713937
• 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.

地球上每天都会经历潮汐，在天界也广泛发生。在这里，我建议研究它们的两种表现形式。 热木星。第一个已知的太阳系外行星群，以难以置信的近距离绕恒星运行。它们通常被认为是动态迁移的产物：它们的形成距离比当前位置更远，与邻居（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；当这些行星周期性地绕其恒星摆动时，它们会引发强烈的潮汐。如果潮汐晃动能够消散成热量，行星轨道就会衰变，一颗热木星就会诞生。这种动力迁移理论虽然巧妙地解释了许多观测到的热木星特征，但也存在许多重大缺陷——所有这些都与我们对潮汐过程缺乏了解有关。因此，为了牢固地确立热木星的起源，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当前的轨道和大小。最终了解大自然产生的这类奇特物体将是令人满足的。 当一颗小行星非常靠近大质量天体（行星或恒星）的表面时，就会发生另一种非常极端的潮汐过程。以前的尸体可以被撕成数以百万计的小碎片，其中一些碎片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景，在传统图景中，人们假设大量的星子在早期无法融入行星，但在数十亿年的时间里留在了后面并逐渐磨成尘埃。我建议研究潮汐破坏事件的细节，以预测其可能产生的频率和碎片盘的出现。 这样的工作也适用于我们太阳系中的柯伊伯带天体。