minor semi-axis

例句：

1. 1.The planet's rotational period is determined by the length of its major and minor semi-axes.
   行星的旋转周期由其主要和次要半轴的长度决定。
2. 2.The astrophysicist used a telescope to measure the distance between the stars and calculate the orbital elements of the two planets.
   天文学家使用望远镜测量了两颗星球之间的距离，并计算了它们的轨道元素。
3. 3.The scientists discovered that the minor semi-axis of the binary system was significantly shorter than expected.
   科学家们发现双星系统的次要半轴明显比预期短。