遥远星体在太阳引力作用下形成的爱因斯坦环

Einstein's ring of a distant star formed by the sun's gravity

当遥远星体,太阳以及观测者在一条直线上时,由于星光在太阳引力场中的偏折效应将形成爱因斯坦环.忽略太阳自转,其外部引力场可用史瓦西度规描述.运用椭圆积分严格地求出零测地线的精确解,并从精确解反解出观测者的径向坐标.从零测地线的精确解可计算出观测者与太阳的距离必须大于或等于547.7天文单位才能观测到星光在太阳引力作用下产生的爱因斯坦环,但是爱因斯坦环几乎和太阳边缘重叠在一起,目前的技术难以分辨.

When a distant star,the sun and the observer are in a line,the Einstein’ s ring can be viewed. Ignoring rotation of the sun,the gravitational field of solar system is described by Schwarzschild metric and then thenull geodesic equation is solved exactly by elliptic integral.It must be apart from the sun at least 547.7 AU to observe the Einstein’ s ring. However,the diameter of Einstein’ s ring and the sun’ s edge almost overlap each otherso that it is very difficult to distinguish them under current technology.