Origins of Spin-Orbit Misalignments in Extrasolar Planetary Systems

最早的太阳系外行星搜索发现了一类意想不到的巨行星，它们的轨道距离主恒星的距离是地球到太阳距离的20倍。这些行星是如何来到离主星这么近的轨道上的，变得更加令人困惑，因为最近的观测表明，其中一些行星的轨道方向与恒星的自转方向不一致，这与我们太阳系中的行星不同。PI将对塑造行星系统的关键物理过程进行全面的理论研究，包括我们自己的系统。该项目将为研究生的培养奠定坚实的基础。PI还将通过加州理工大学的“暑期研究连接”项目指导高中生。这项理论/计算研究将专注于协调由星云驱动的巨型行星的平稳迁移和通过圆盘扭转机制实现的大自旋-轨道失调。我们将考察多个恒星系统内的动力学演化对行星形成盘大尺度结构的影响，并量化恒星自旋轴混沌演化的可能性。我们将严格分析失准幅度与磁力和引力盘星耦合的特定模式之间的关系，并着眼于解释观测到的轨道倾角和恒星有效温度之间的关联。

The earliest searches for extrasolar planets uncovered an unexpected class of giant planets that orbit twenty times closer to their host stars than the Earth does to the Sun. Just how these planets came to orbit so close to their host star has become even more perplexing, as recent observations have shown that some of these planets orbit in direction that does not correspond with the star's spin, unlike planets in our solar system. The PI will conduct a comprehensive theoretical study of the key physical processes that act to sculpt planetary systems, including our own. This project will provide a strong basis for the training of a graduate student. The PI will also mentor high school students through Caltech's "summer research connection" program.This theoretical/computational investigation will focus on reconciling smooth nebular-driven migration of giant planets and large spin-orbit misalignments through the disk-torquing mechanism. The effects of dynamical evolution within multiple star systems on the large-scale structure of the planet-forming disks will be examined, and the possibility of chaotic evolution of stellar spin axes will be quantified. The dependence of the misalignment amplitude on the specific modes of magnetic and gravitational disk-star coupling will be critically analyzed, with an eye towards explaining the observed correlation between orbital obliquity and stellar effective temperature.