Disk and Wind Accretion to Magnetized Stars

磁化恒星的盘和风吸积

• 批准号: 0307817
• 负责人: Richard Lovelace
• 金额: --
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2006-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0307817&HistoricalAwards=false
• 关键词: Disk; Wind; Accretion; Magnetized; Stars

Lovelace, Richard V.AST 0307817A wide range of stars has significant magnetic fields. They typically represent either very early stages of stellar evolution (so-called T Tauri stars), which carry important information about the formation of stars and protoplanetary disks, or end stages of evolution (white dwarfs, neutron stars), which consist of exotic matter and carry information about the evolutionary paths of stars in our Galaxy. The observable properties of these stars strongly depend on the accretion rate of material to their surface, on the pattern of matter flow in the magnetospheres around them, and on the interaction of magnetic field lines with the surrounding matter. Observations, however, are not sufficient to understand the processes in these systems because the spatial details remain unresolved. Nor can the problem of disk or wind accretion to a magnetized star be solved analytically. Thorough two- and three-dimensional simulations are necessary to understand the physics of plasma flow around magnetized stars. In this project the investigators are concentrating mainly on three dimensional simulations of several problems which are important for the understanding of the observations. These include simulations of disk accretion to a star with a dipole magnetic field at different inclination angles of the magnetic pole, different rotation rates of the star, different mass accretion rates, and simulations of accretion directly to a strongly or weakly magnetized star. The simulations will supply the necessary models to interpret observations of different astronomical objects.Broader impact: This research continues to attract many undergraduate and graduate students. Training students is considered an important part of the overall project. Typically, four to six undergraduate students work on different parts of the project, and one to two graduate students work on longer-term projects gaining experience with scientific research. They learn magnetohydrodynamics and programming, perform simulation runs with different parameters, and learn how to analyze data using different tools including visualization and animation. The developed methods and numerical codes also have general value and are applicable in other areas of science: planetary science, geophysics, magnetosphere science, solar science, and in engineering.

Lovelace，Richard V.AST 0307817A广泛的恒星具有明显的磁场。它们通常代表了恒星进化的很早阶段（所谓的T Tauri恒星），该阶段具有有关恒星和原行星磁盘形成的重要信息，或者是进化的末端阶段（白矮星，中子星），这些阶段由外来物质和有关我们Galaxy中星星进化途径的信息组成。这些恒星的可观察特性在很大程度上取决于其表面的材料积聚速率，周围磁层中的物质流动模式以及磁场线与周围物质的相互作用。但是，观察结果不足以理解这些系统中的过程，因为空间细节仍未解决。分析磁盘或磁盘的磁盘或风吸积问题也不能分析解决。必须进行彻底的二维模拟，以了解磁化恒星周围血浆流的物理。 在这个项目中，研究人员主要集中于三个维度模拟的几个问题，这些问题对于理解观察至关重要。其中包括将磁盘积聚到具有偶极磁场在磁极的不同倾斜角，恒星的不同旋转速率，不同的质量吸积率的不同旋转速率的模拟，并直接将积聚的质量吸积速率以及直接降低到强或弱磁性的恒星。 模拟将提供必要的模型来解释对不同天文对象的观察结果。BROADER的影响：这项研究继续吸引许多本科生和研究生。培训学生被认为是整个项目的重要组成部分。通常，四到六个本科生从事项目的不同部分工作，一到两位研究生从事长期项目，从而获得了科学研究的经验。 他们学习磁性水力动力学和编程，使用不同的参数进行模拟运行，并学习如何使用不同的工具（包括可视化和动画）分析数据。 开发的方法和数值代码也具有一般价值，并且适用于其他科学领域：行星科学，地球物理学，磁层科学，太阳能科学和工程学。