Short answers, pulled from the story.
Otto Struve stood before the scientific community in 1952 and proposed that powerful spectrographs could detect distant planets by measuring the tiny wobbles of their parent stars. He suggested that a massive planet like Jupiter would cause its star to shift slightly as both objects orbited a common center of mass.
In November 1995, the team published their findings regarding 51 Pegasi b in the journal Nature. This discovery marked the first planet confirmed to orbit a main-sequence star using Doppler spectroscopy after installing the ELODIE spectrograph at the Haute-Provence Observatory during 1993.
The HARPS spectrograph identifies shifts as small as 0.3 meters per second. Such precision allows astronomers to locate many possibly rocky Earth-like planets that earlier instruments missed.
If the orbital plane lines up perfectly with the observer's view, the measured variation equals the true value. A tilted orbital plane means the true effect is greater than the measured variation in radial velocity, so the planet's actual mass will always be greater than the minimum calculated value derived from these measurements.
Pluto generates a negligible 0.00003 meters per second signal undetectable by current technology. This figure illustrates why massive objects in tight orbits remain the primary targets for detection compared to smaller bodies like Pluto.