original question: Which astronomical discovery use [Doppler spectroscopy (radial velocity)]?
answer: hd 102272 c, hd 68988 b, hd 12661 c...
answer type: Astronomical Discovery.
auxiliary information: Doppler spectroscopy is an indirect method for finding extrasolar planets and brown dwarfs 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.
Witch extrasolar planets and brown dwarfs were discovered using [Doppler spectroscopy (radial velocity)]