Observations of Cool-Star Magnetic Fields
Observations of Cool-Star Magnetic Fields
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DOI：
10.12942/lrsp-2012-1
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发表时间：
2012-02
影响因子：
20.9
通讯作者：
A. Reiners
中科院分区：
文献类型：
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作者：
A. Reiners
像太阳这样的冷星拥有能够产生相当大的表面磁场的对流区，从而导致恒星的磁性活动。恒星参数，如自转、半径和年龄对冷星磁性的影响，以及辐射核心和对流包层之间的剪切层对于磁场产生的重要性，是我们理解低质量恒星发电机、太阳发电机以及其他大型和行星发电机的关键。在过去的几年里，我们对冷星磁场的观测图像有了极大的改进。人们开发了复杂的方法来寻找磁场的微妙效应，这种效应很难探测到，特别是在凉爽的恒星中。在强调现代方法用于测量冷恒星中的磁性的假设和能力的同时，我回顾了可用于磁场测量的不同技术。我收集了对冷星磁场的分析，并试图比较不同方法的结果，我还回顾了导致我们目前的磁场图像及其在冷星和棕矮星中产生的经验证据。
Cool stars like the Sun harbor convection zones capable of producing substantial surface magnetic fields leading to stellar magnetic activity. The influence of stellar parameters like rotation, radius, and age on cool-star magnetism, and the importance of the shear layer between a radiative core and the convective envelope for the generation of magnetic fields are keys for our understanding of low-mass stellar dynamos, the solar dynamo, and also for other large-scale and planetary dynamos. Our observational picture of cool-star magnetic fields has improved tremendously over the last years. Sophisticated methods were developed to search for the subtle effects of magnetism, which are difficult to detect particularly in cool stars. With an emphasis on the assumptions and capabilities of modern methods used to measure magnetism in cool stars, I review the different techniques available for magnetic field measurements. I collect the analyses on cool-star magnetic fields and try to compare results from different methods, and I review empirical evidence that led to our current picture of magnetic fields and their generation in cool stars and brown dwarfs.