sidereal year

sidereal-year的词性：
n.（名词）

1. The time required for one complete revolution of the earth about the sun, relative to the fixed stars, or 365 days, 6 hours, 9 minutes, 9.54 seconds in units of mean solar time.
恒星年：以固定恒星为参照物，地球围绕太阳公转一整周所需要的时间，用标准太阳时单位计为365天6小时9分9.54秒