Astrometric Research in the Southern Hemisphere

南半球的天体测量研究

• 批准号: 8917717
• 负责人: William Van Altena
• 金额: --
• 依托单位: Yale Southern Observatory, Inc.
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-01-01 至 1993-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8917717&HistoricalAwards=false
• 关键词: Astrometric; Research; Southern; Hemisphere

Dr. Van Altena will continue his Southern Proper Motion (SPM) program. These are second epoch observations, the first epoch data were obtained between 1965 and 1974, which are taken at the Yale Southern Observatory at El Leoncito, Argentina. The goal of the project is to determine the absolute proper motions of stars with respect to faint galaxies. The 20-year difference in the two data sets should result in highly accurate measurements of proper motions. The absolute proper motions will be used to determine the absolute magnitudes of RR Lyrae stars, corrections to the constants of precession, a fixed reference frame for the HIPPARCOS astrometric satellite, Oort's constant B, and to study the local structure of the Galaxy. The problems associated with establishing an inertial reference frame have occupied astronomers for millenia. With the passage of time and improvements in measurement techniques, it was discovered that the stars are not fixed in the sky and that it is necessary to separate the motions of the stars from that of the Earth's pole. This separation is currently made through the observation of Solar System objects such as the Sun, the planets, and minor planets. However, some of the Solar System observations are made in modes that differ significantly from those used in normal stellar observatons, and this difference may compromise the connection between the dynamically defined reference frame and the stellar frame. As a result, astronomers are left with star streams, moving groups, and non-circular motions in the Galaxy to complicate the stellar motion model and the derivation of the corrections to the constants of precession. The initial impetus for determining proper motions with respect to faint galaxies was to determine the corrections to the constants of precession and thereby improve on the system of the fundamental catalogs.

货车阿尔特纳博士将继续他的南方自行（SPM）计划。这些是第二个历元的观测，第一个历元的数据是在1965年至1974年之间获得的，这些数据是在阿根廷埃尔莱昂西托的耶鲁南方天文台拍摄的。该项目的目标是确定恒星相对于暗星系的绝对自行。两个数据集之间20年的差异应该会导致对自行的高度精确测量。绝对自行将用于确定天琴座RR星的绝对星等、岁差常数的修正、依巴谷天体测量卫星的固定参考系、奥尔特常数B，以及研究银河系的局部结构。建立惯性参考系的问题已经困扰了天文学家数千年。随着时间的推移和测量技术的改进，人们发现星星在天空中并不固定，有必要将星星的运动与地球的极点分开。目前，这种分离是通过观察太阳系天体，如太阳，行星和小行星来实现的。然而，一些太阳系观测的模式与普通恒星观测的模式有很大的不同，这种差异可能会损害动态定义的参考系和恒星系之间的联系。因此，天文学家们只剩下银河系中的星星流、运动的星群和非圆周运动，使恒星运动模型和岁差常数修正的推导变得复杂。确定暗星系自行的最初动力是确定岁差常数的修正，从而改进基本星表系统。