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Kepler Radius

(radius at which a particular velocity would orbit)

Kepler Radius and similar term Keplerian Radius are terms I can find no definition for.

I speculate it might be the radius of a Keplerian Orbit that would produce a given observation: for example, if apparent the Doppler Shift of Spectral Lines of a disk, planet, or Binary Star companion indicate Radial Velocities implying some Orbital Speed, the Kepler radius would be the radius suggested by Kepler's Laws.

Another possible use, for a disk in which other forces contribute to the orbital speeds (e.g., gas pressure, Radiation Pressure), would be a radius of the disk at which those other forces cancel and the orbital speed is that of a Keplerian orbit.

The phrase also arises in discussion of Kepler Telescope discoveries, e.g., Kepler Radius Distribution, which could be the distribution of Extra-Solar Planet radii in samples of Kepler discoveries.