2000年以来国际天文学联合会(IAU)关于基本天文学的决议及其应用

Explanation and Implementation of the IAU 2000/2006 Resolutions on Fundamental Astronomy

1991年以来,在国际天文学联合会(IAU)全体大会上,通过了一系列关于天文参考系、时间尺度和地球自转模型的决议,其目的是为了适应不断提高的天文观测精度。其中最重要的3次,分别是在1997年的京都,2000年的曼彻斯特和2006年的布拉格通过的IAU 1997,IAU 2000和IAU 2006决议,主要的变化包括:从与历元有关的动力学参考系到与历元无关的运动学参考系,从参考系的恒星实现到河外射电源实现,从春分点到无旋转原点,以及岁差-章动模型的改进。由于这些决议在参考系转换等方面引入了很多新概念和新方法,对教学、研究和应用都产生了不小的影响,对它们进行解读,澄清概念,规范使用是有必要的。首先介绍IAU关于时间尺度和天文参考系的重要决议,并重点介绍IAU 2000和2006的每一条决议:然后详细介绍其应用:包括时间系统,国际天球参考系和岁差-章动模型,并和对应的旧系统进行比较;最后对这些决议的使用提出建议。

With the rapid increasing accuracy of the observations and development of theoretical models, the International Astronomical Union （IAU） adopted in 2000 and 2006 a series of resolutions which modified the astronomical reference systems and the Earth rotation model. These resolutions introduce new concepts and definitions in astronomical references： the main changes are from bright stars to extragalactic reference sources, from a reference frame moving with time （FK5） to a fixed reference frame （ICRS） independent of time, and from a precessing equinox to a more stable fiducial point （the non-rotating origin）. At the same time, the IAU 2000/2006 resolutions recommend new paradigms and high accuracy models in the transformation between the terrestrial and celestial reference systems. This paper reviews the consequences of these resolutions on the fundamental reference systems, time scales in the framework of general relativity, current IAU precession-nutation models, and comparisons of them with traditional ones. Recommendations are given concerning the concepts, nomenclature, models and conventions that are suitable for modern and future realizations of the reference systems.