Spectroscopic observations show that the spectral lines of HDE 226868 shift back and forth with a period of 5. 6 days.是什么意思_Spectroscopic observations show that the spectral lines of HDE 226868 shift back and forth with a period of 5. 6 days.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句