Symbol r

The passage around this formula

…close to the companion star, because the companion’s gravity curves the spacetime the pulse crosses. The delay as a function of orbital phase $\phi$ is standardly written $\Delta_S(\phi) = -2r\,\ln\!\left[1 - s\sin\phi\right]$. where the “range” parameter r is set directly by the companion’s mass and the “shape” parameter s by the orbit’s inclination. Because r and s are measured independently of the pulsar’s own mass, and Kepler’s laws already fix the total system mass from the orbital period and velocity, a sufficiently edge-on, sufficiently…

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