Migration and Survival of Exoplanets near Magnetized Young Stars

康奈尔大学的一个研究小组进行的一项研究调查将模拟主恒星磁场影响下行星的轨道迁移。观测提出了一个重要的问题：被认为远离主星形成的大型气态行星，往往被发现绕其主星非常近的轨道运行。人们认为，气体行星在形成后，由于气体和尘埃盘内的摩擦而失去角动量，从而向其所在恒星迁移。然而，目前还不清楚为什么这些行星不会落入恒星。当今行星科学中的一个重要问题是了解它们是如何在如此接近其宿主恒星的地方生存下来的。该团队将通过超级计算机模拟来研究恒星磁场在行星的生存和轨道分布中所起的作用。他们还将在当地的科学中心开发一个新的桌面天文展览。展览将教育公众关于磁铁的特性以及地球和太阳的磁场，并为2024年的日全食做好准备，日全食将在纽约州伊萨卡附近可见。一名研究生将积极参与行星轨道的建模，并在科学中心向公众解释科学。旋转磁化恒星附近行星的迁移将在全球数值模拟中进行研究。这项研究将增进对年轻磁化恒星在系外行星迁移和生存中所起作用的理解。具体地说，他们将(1)调查行星在磁层空洞内的迁移和生存，考虑到它们与内盘的相互作用；(2)调查由于大转力矩而在盘腔边界处的低质量行星的迁移和捕获，以及(3)研究外行星与其内盘中的波的相互作用是否会改变其轨道的偏心率和倾角。这项研究将使用三维磁流体力学代码：第一个是柱坐标下的代码，其中包括网格细化；第二个是立方体球体代码，它在过去被广泛用于模拟磁化恒星的吸积。这两个代码都包括一个计算行星轨道的行星模块。这一裁决反映了NSF的法定任务，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

A research investigation conducted by a team from Cornell University will simulate the orbital migration of planets under the influence of a host star's magnetic field. Observations present an important problem: large, gaseous planets that are thought to form far from their host stars are often found to orbit very close to their host stars. It is thought that after forming, gas planets migrate towards their host stars by losing angular momentum to friction within a disk of gas and dust. However, it is not understood why these planets do not fall into the star. An important problem in the science of planets today is understanding how they survive in such close proximity to their host stars. This team will investigate through supercomputer simulations what role the stellar magnetic field plays in the survival and orbital distribution of planets. They will also develop a new tabletop astronomy exhibit at the local Sciencenter. The Exhibit will educate the public about the properties of magnets and the magnetic fields of the Earth and Sun, and it will prepare them for the total Solar eclipse of 2024, which will be visible near Ithaca, NY. One graduate student will be actively involved in the modeling of planetary orbits and in explaining science to the public at the Sciencenter. Migration of planets in the vicinity of rotating magnetized stars will be studied in global numerical simulations. The investigation will advance understanding of the role that young magnetized stars play in the migration and survival of exoplanets. Specifically, they will (1) investigate the migration and survival of planets inside magnetospheric cavities, taking into account their interaction with the inner disk; (2) investigate migration and trapping of low-mass planets at disk-cavity boundaries due to corotation torque, and (3) study whether interactions of exoplanets with waves in their inner disks can change eccentricities and inclinations of their orbits. The investigation will use three-dimensional magneto-hydrodynamic codes: the first a code in cylindrical coordinates, which incorporates mesh refinement, and secondly the Cubed Sphere code, which has been used extensively in the past for modeling accretion onto magnetized stars. Both codes include a planetary module that calculates the orbits of planets.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.