Constraints on the hypothetical planet in the obliquity-tide scenario, under assumptions that lend the hypothesis maximum credence. RV amplitudes are indicated by the background color (assuming i₂ = 90^∘). The blue line shows the minimum a₂ compatible with Hill stability, and the white line is the lower limit imposed by angular-momentum conservation, leaving the brightly colored region as the parameter space allowed by the theory. The green line is the upper limit imposed by the RV data, which excludes all of the allowed parameter space.