High-Resolution Imaging of Stellar Surfaces

在天文成像中，为了获得最高的空间分辨率，能够分辨出天空中最精细的尺度结构，观测技术是将相距很远的多台望远镜发出的光组合在一起。众所周知，这种干涉仪所获得的空间分辨率大致相当于一个直径等于单个望远镜间距的巨型望远镜的分辨率。干涉测量的技术挑战很大，因为光必须在光学波长尺度上极其稳定的仪器中汇集。光学干涉测量的科学目标是研究恒星，特别是恒星表面，这是本项目的主题。该项目将对海军精密光学干涉仪（NPOI）进行一系列升级，最终使恒星表面分辨率元素的数量比现有仪器增加10-20倍或更多，并进一步允许生产时间分辨率为几天的恒星图像。该项目将采用基线自启动、相干积分和图像重建等干涉测量技术，显著提高NPOI对恒星表面成像的能力。科学上的好处将是巨大的，并且可能包括对其他光学干涉测量领域的重大影响。没有其他技术可以提供这种由这些发展所带来的科学。这些研究的进展，在揭示关于恒星的新知识方面，无疑将提高我们对我们自己的太阳和太阳活动周期的理解。太阳活动对地球生命的许多方面都有至关重要的影响，可能包括天气。该项目由美国国家科学基金会天文科学部通过其先进技术和仪器计划提供资金。

In astronomical imaging, the observational technique for achieving the highest spatial resolution, capable of discerning the finest-scale structure on the sky, is to combine the light from multiple telescopes separated by substantial distances. As is well known, the spatial resolution achieved by such an interferometer is roughly as good as that of a single giant telescope of diameter equal to the individual telescope separations. Technical challenges with interferometry are large, as the light must be brought together in instrumentation that is extremely stable mechanically, on the scale of optical wavelengths. A scientific target of continuing promise for optical interferometry is the study of stars, and stellar surfaces in particular, the subject of this project.This project will conduct a set of upgrades to the Navy Precision Optical Interferometer (NPOI) that will ultimately enable an increase in the number of resolution elements on the surface of a star by a factor of 10-20 or more over existing instruments, and will furthermore allow the production of stellar images with time resolution of a few days. This project will implement the interferometric techniques of baseline bootstrapping, coherent integration, and image reconstruction, significantly enhancing the capabilities of NPOI for imaging stellar surfaces. The science benefits will be major, and may include major impacts in other areas of optical interferometry. No other technique could deliver the kind of science that will be enabled by these developments.These research advances, in uncovering new knowledge about stars, will no doubt improve our understanding of our own sun and the solar activity cycle. Solar activity has vitally important impacts on many aspect of life on earth, possibly including the weather.Funding for this project is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.