太阳物理研究组知识库

太阳半径是指从太阳球心到光球层外边界的距离。测量太阳半径历史悠久,系统性测量始于19世纪,其标准值为959.63〃。主要有以下几种测量方法:(1)子午圈测量;(2)日食和水星凌日;(3)望远镜漂移扫描技术;(4)等高方法;(5)卫星角距离测量。对于太阳半径的研究,主要集中在以下三类观点:一是认为太阳半径在缩小;二是认为太阳半径基本没有变化;三是认为太阳半径变化与一些太阳活动指数有关联,并具有自身的运动规律。太阳半径是否变化,如何变化,目前尚无定论。首先介绍了太阳半径,回顾了太阳半径的观测方法;接着介绍了目前太阳半径的主要研究观点;最后对将来的研究提出一些看法。

Solar radius is the distance from the center of the Sun to the outer boundary of the photo-sphere. The solar radius has been measured systematically since 19th century. The adopted standard value of the solar radius is 959.6300published by Auwers in 1891. From ancient to now, a variety of instruments and different methods have been used to measure the solar radius: (1) Meridian circle measurements(Greenwich Royal Observatory);(2) Solar eclipse and Mercury transit;(3) Drift-scan technology;(4) Danjon solar style astrolabes(the Calern Observatory and the Tubitak National Ob-servatory);(5) Satellite direct angular measurement(SOHO/MDI, Picard). Some researchers have reported that the solar radius shows a secular decrease. However, other researchers have reported that the solar radius is stationary. Some researchers have studied the variation of the solar radius with solar activity, the results show that the variations of the solar radius occur over periods of some days to several tens of years. Has the solar radius changed or not? If it changes, how it changes? Accompanied with data from ancient to now, lots of work has been done. It is believed that the variability of the solar radius is a critical probe for our understanding of solar interior stratification, radiation mechanisms, space weather and Earth’s climate. In this paper, we present the history measurement and progress study of the solar radius. In Sect. 2, an overview about different solar radius methods is presented. Sect. 3 describes the different study results. Finally, Sect. 4, a proposal for future study is made.