If you have a binary system whereby both stars are visible so you get the spectrum of both stars, then you see the Doppler shift of both stars in the spectrum.
若存在一个双星系统，两颗恒星均看不见，你能得到双星的光谱，然后在光谱中看到，双星的多普勒顿移。
2
And this spectrum a, the top spectrum, is of a star, a binary system, that has a period of 20.5 days.
这个光谱a，顶上的光谱，是一颗恒星的，在双星系统中，周期是20。5天。
3
It will also increase the spectrum of our choices, beyond the binary options of "Yes" or "No" referenda.