Stellar Wobble
Doppler spectroscopy (also known as the radial velocity method, or colloquially, the wobble method) is an indirect method for finding extrasolar planets from radial velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star.
About half of the extrasolar planets known were discovered using Doppler spectroscopy, as of October, 2012.
Read more about Stellar Wobble: History, Procedure, Radial Velocity Comparison Tables, Problems, See Also