High Sensitivity Array Studies of Stellar Radio Coronae

恒星射电日冕的高灵敏度阵列研究

• 批准号: 0908941
• 负责人: Robert Mutel
• 金额: $ 40.91万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0908941&HistoricalAwards=false
• 关键词: Sensitivity; Array; Studies; Stellar; Radio; Sensitivity; Array; Studies; Stellar; Radio

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Dr. Robert L. Mutel of the University of Iowa and his students will undertake a research program to image the radio coronae of several active late-type binary stars at multiple epochs with unprecedented sensitivity, angular resolution, and positional accuracy. The systems will be imaged using the High Sensitivity Array (HSA), the world's most powerful radio imaging long-baseline array. The program will combine the imaging power of the HSA with observational strategies that optimize positional accuracy, allowing registration of the component star positions on the radio maps with an absolute accuracy approximately one stellar radius. These images will reveal, for the first time, the relationship between extended radio coronae and the parent star system: Whether the radio emission originates on a single star or is generated in the inter-binary region, whether large-scale coronal loops exist, and if radio flares arise near the stellar surface or perhaps at the top of loops. In addition to stellar astrophysical results, fundamental parameters such as distance, proper motion, and binary orbital orientation will be determined with an accuracy significantly better than current ground- or space-based optical surveys. The multi-epoch HSA radio maps will allow the first detailed, systematic determination of the morphology of the radio coronae of late-type active stars. This is vital in testing existing models of stellar coronae, which are largely based on spectral measurements of the integrated radio and/or x-ray corona, with little or no spatial information. One key test will be to resolve competing hypotheses of radio coronal geometry, such as polar models, dipole traps, and accretion disk-driven inter-binary emission regions. Another will be to establish whether large-scale magnetic loops or other structures are a common feature in active stellar coronae, and if so, to establish their sizes and temporal evolution.High-fidelity radio maps, combined with accurate overlaid stellar positions, will significantly guide development of comprehensive models of stellar coronae which incorporate x-ray, optical, and UV observations in a unified theoretical framework. Also, since the target stars are all optically bright, the ability to measure stellar radio positions with high accuracy will be very useful in tying the optical and radio coordinate frames together with sub-milliarcsecond precision. This is a long-standing goal vital to many astrophysical disciplines, including future astrometric space missions such as Gaia and PlanetQuest.

该奖项是根据2009年《美国回收与再投资法》（公共法第111-5）.DR资助的。爱荷华大学及其学生的罗伯特·L·穆特尔（Robert L.该系统将使用高灵敏度阵列（HSA）（世界上最强大的无线电成像长基线阵列）进行成像。该程序将将HSA的成像能力与观察策略相结合，以优化位置准确性，从而以大约一个恒星半径的绝对精度来注册零件星形位置。这些图像将首次揭示出延长的无线电冠状动脉与母星系统之间的关系：无线电发射是起源于单星还是在二进制区域中产生，无论是大规模的冠状环，是否存在大规模的冠状环，以及是否在恒星表面附近或可能在循环的顶部出现无线电耀斑。 除了恒星的天体物理结果外，还将确定诸如距离，正确运动和二元轨道取向等基本参数，其精度明显优于当前基于地面或空间的光学调查。多上述HSA无线电图将允许对晚期活性星的无线电冠形的形态进行第一个详细的系统测定。这对于测试恒星冠的现有模型至关重要，这主要基于集成无线电和/或X射线电晕的光谱测量值，几乎没有空间信息。一个关键测试将是解决无线电冠状几何形状的竞争假设，例如极性模型，偶极子陷阱和积聚磁盘驱动的二进制发射区。 Another will be to establish whether large-scale magnetic loops or other structures are a common feature in active stellar coronae, and if so, to establish their sizes and temporal evolution.High-fidelity radio maps, combined with accurate overlaid stellar positions, will significantly guide development of comprehensive models of stellar coronae which incorporate x-ray, optical, and UV observations in a unified theoretical framework.同样，由于目标恒星在光学上都是光亮的，因此以高精度测量恒星无线电位置的能力将非常有用，可与次米利亚克秒的精度一起将光学和无线电坐标框架加上。对于许多天体物理学科，包括未来的天文空间任务，例如盖亚和行星奎斯特，这是一个至关重要的目标。