UBVRI Photometric Standard Stars

这个研究项目的目标是增强、发展和发布微弱的标准恒星序列。长期以来，需要在各种光学波长下具有已知强度和颜色的精确光度标准恒星。使用这样的标准恒星，可以将不同研究人员对不同天体现象的亮度和颜色测量结果进行组合和相互比较。应用的例子包括校准天体的星等和色指数，以进一步了解恒星演化、星团的年龄和距离、变星的研究，以及定义从我们的银河系、本星系群直至宇宙边缘的距离尺度。在这里，兰多尔特博士将利用智利塞罗·托洛洛美洲天文台（Cerro Tololo Interamerican Observatory）的望远镜，完成新标准恒星的研制，这些恒星的亮度将比现有恒星暗100倍左右。他还将在亚利桑那州的基特峰国家天文台开始研究下一组更暗淡的标准恒星。这些校准星是所有最大的地基和天基光学探测器（包括目前已建成的、正在建设的和正在规划阶段的）所需要的，也将被它们所使用。该项目的总体目标是将校准序列扩展到更模糊的限制，以便解释的限制将是科学的，而不是校准的限制。

The goal of this research project is to enhance, develop, and publish faint standard star sequences. There is a long-term need for accurate photometric standard stars with known intensities and colors at a variety of optical wavelengths. Use of such standard stars permits the combination and inter-comparison of the brightness and color measurements of different celestial phenomena made by different investigators. Examples of uses include the calibration of magnitudes and color indices of celestial objects to further the understanding of stellar evolution, ages and distances of star clusters, studies of variable stars, and to define the distance scale through our Milky Way Galaxy, the local group of galaxies, and onward to the edge of the Universe. Here, using telescopes at the Cerro Tololo Interamerican Observatory in Chile, Dr. Landolt will complete the development of new standard stars that will be about 100 times fainter than those now available. He will also begin development of the next set of even fainter standard stars at the Kitt Peak National Observatory in Arizona. These calibration stars are needed for, and will be usable by the entire ensemble of the largest ground-based and space-based optical detectors, both presently built, those under construction, and those in the planning stage. The overall goal of this project is to extend the calibration sequences to fainter limits so the limits of interpretation will be scientific, and not those of calibration.