Multi-Wavelength Observations and Modeling of Magnetic Fields in Ultracool Dwarfs and Giant Exoplanets

质量最低、温度最低的恒星被称为超冷矮星(UCD)，也是数量最多的恒星。由于内部完全对流，它们在历史上被认为没有发电机产生的磁场。最近的观测表明，这些恒星确实存在磁活动。这项工作将描述这种磁活动的性质，并导致对这些恒星中负责磁场的发电机的理解。了解这些发电机将会照亮最大的系外行星的工作原理。该项目将吸引博士后学者和本科生。此外，这项工作将通过学生积极参与使用哈佛-史密森望远镜纳入本科教育。该项目的结果将通过哈佛-史密森天文台之夜计划的讲座和大众出版物上的持续宣传向公众传播。该小组将检查来自VLA和ALMA的档案数据，以及泛星中深探测(PS1/MDS)，以了解各种超冷矮星(UCD)的磁场。他们将研究(一)磁场强度的分布；(二)磁场的物理尺度、拓扑学和相干时间尺度；(三)发电机在整个UCD范围内的普遍存在，以及首次在巨大的系外行星中的情况；(四)PS1/MDS中大约100,000个UCD在几分钟到几年的时间尺度上的闪耀活动的速率和能量，对UCD周围的宜居性的影响。结果将为未来无线电设施(例如，平方公里阵列)和光学测量(例如，与NSF的Vera Rubin天文台进行的遗留空间和时间调查)的研究提供信息。该奖项反映了NSF的法定使命，并已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。

The stars with the lowest mass and lowest temperature, called Ultra-Cool Dwarfs (UCDs), are also the most numerous. With fully convective interiors, they historically were thought not to have dynamo-generated magnetic fields. Recent observations have shown that these stars do indeed have magnetic activity. This work will characterize the nature of this magnetic activity, and lead to an understanding of the dynamo responsible for magnetic fields in these stars. Understanding these dynamos will shine light on the workings of the largest exoplanets. The project will engage post-doctoral scholars and undergraduate students. In addition, the work will be incorporated into undergraduate education through the active participation of students in using Harvard-Smithsonian telescopes. The results of the project will be disseminated to the public through talks in the Harvard-Smithsonian Observatory Night program as well as through on-going outreach in popular publications.The team will examine archival data from the VLA and from ALMA, as well as the Pan-STARRS Medium Deep Survey (PS1/MDS) to understand magnetic fields from a variety of ultra-cool dwarf (UCD) stars. They will study (i) the distribution of magnetic field strengths; (ii) the physical scale, topology, and coherence timescale of the magnetic fields; (iii) the ubiquity of dynamos across the full range of UCDs, as well as for the first time in giant exoplanets; and (iv) the rates and energetics of flaring activity in about 100,000 UCDs in the PS1/MDS on timescales of minutes to years, with implications for habitability around UCDs. The results will inform studies with future radio facilities (e.g., Square Kilometer Array) and optical surveys (e.g., the Legacy Survey of Space and Time with NSF’s Vera Rubin Observatory).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.