Detailed Instructions: Compose a new way to ask the same question. The new question must be asking the exact same thing as the original question does. Without any other information, you should be able to tell that the original question and the new question are the same. Preserve bracketed phrases in your new question. You can change the rest of the question provided the above requirements are satisfied. The new question must have a natural, fluent formulation, as if it were composed by a native English speaker. You will be given three pieces of information to help you create better questions. Those are: "Answer": the answer to the question, e.g., "Honolulu". "Answer Type": the type of the answer, e.g., "Location". "Auxiliary Information" is a detailed description of some concepts mentioned in the question, if any.
Q: 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.
A:
in what astronomical discovery is it used [Doppler spectroscopy (radial velocity)]?