Observational Studies of Magnetic Fields in Very Low Mass Stars

极低质量恒星磁场的观测研究

• 批准号: 1614770
• 负责人: Edo Berger
• 金额: $ 35.6万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1614770&HistoricalAwards=false
• 关键词: Observational; Studies; Magnetic; Fields; Very

This is an observational study of the magnetic fields of the smallest stars. These stars have such low temperature and low mass that they are called ultracool dwarfs (UCDs). UCDs are the most common type of star in the Galaxy and they have a surprising amount of magnetic activity that is not understood. This project will address several fundamental questions about UCDs, including how strong are their magnetic fields, how are they distributed around the star, and how do they change over time. Results from this project will also be helpful for studies of the magnetic fields of giant planets around other stars. Undergraduate and graduate students will be trained and mentored in research. They will participate in all stages of the work, including collecting, analyzing, and publishing data at many different wavelengths. The project will also integrate research experiences into undergraduate education and public lectures.This project will exploit a unique set of magnetic activity observations from radio wavelengths to X-rays. The group will measure magnetic field strengths, spectral energy distributions, and time monitoring using radio observations with the Jansky Very Large Array (JVLA) and ALMA telescopes. They will document and analyze UCD flares and variability with optical observations using the Pan-STARRS Medium-Deep survey. The role of rotation in convective dynamos will also be studied with X-ray observations that the team obtained from the Chandra telescope. This project will determine the fundamental properties of convective magnetic dynamos, and the resulting range of magnetic activity timescales and energetics. The observations will provide empirical inputs for analytical models and numerical simulations of convective magnetic dynamos. In addition, the study of flares and variability in a million UCD stars on timescales of minutes to years will impact the question of life and habitability in the compact habitable zones of M dwarfs, a popular target population for Earth-like exoplanet searches.

这是对最小恒星磁场的观测研究。 这些恒星具有如此低的温度和质量，因此被称为超冷矮星（UCD）。 UCD是银河系中最常见的星星类型，它们有着令人惊讶的磁活动，这是不为人所知的。这个项目将解决关于UCD的几个基本问题，包括它们的磁场有多强，它们如何分布在星星周围，以及它们如何随时间变化。该项目的结果也将有助于研究其他恒星周围巨行星的磁场。本科生和研究生将接受研究方面的培训和指导。他们将参与工作的所有阶段，包括收集，分析和发布许多不同波长的数据。该项目还将把研究经验融入本科教育和公开讲座，利用一套独特的从无线电波长到X射线的磁活动观测。该小组将利用Jansky甚大阵列（JVLA）和阿尔马望远镜进行无线电观测，测量磁场强度、光谱能量分布和时间监测。他们将使用Pan-STARRS中深调查记录和分析UCD耀斑和光学观测的变化。旋转在对流发电机中的作用也将通过该团队从钱德拉望远镜获得的X射线观测进行研究。该项目将确定对流磁发电机的基本特性，以及由此产生的磁活动时间尺度和能量范围。观测结果将为对流磁发电机的分析模型和数值模拟提供经验输入。此外，在几分钟到几年的时间尺度上对一百万颗UCD恒星的耀斑和变化的研究将影响M矮星紧凑可居住区的生命和可居住性问题，M矮星是类地系外行星搜索的热门目标人群。