Distant Worlds-radial velocity method

Distant Worlds-radial velocity method

diagram of radial velocity method of locating exoplanets

The radial velocity method, also known as Doppler spectroscopy, relies on the fact that a star moves slightly when it is orbited by a planet, in response to the gravitational tug of the planet. These slight movements affect the star's normal light spectrum, or color signature. When the star moves toward a distant observer, its spectrum shifts slightly toward the blue; when it moves away, the shift is slightly toward the red. As the planet continues to orbit the star, the shifts repeat at regular intervals. These shifts are detected by sensitive spectrographs on Earth.

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