= Binary-pulsar Einstein delay
{title2=$\Delta_E=\gamma\sin E$}
The <binary-pulsar Einstein delay> is the periodic clock-rate contribution to pulse arrival times from a <pulsar> moving in an eccentric binary. Near closest approach, the pulsar's orbital <speed> is larger and the companion's gravitational potential is deeper. <Time dilation> and <gravitational redshift> therefore make its clock run at a different rate relative to a distant time coordinate.
At leading order the variable timing term is $\Delta_E=\gamma\sin E$, with <eccentric anomaly> $E$ and time amplitude $\gamma$. Constant clock-rate offsets are absorbed into the fitted pulsar spin. This term is distinct from the geometric <binary-pulsar Roemer delay> and the propagation <Shapiro time delay>. Fitting it with other orbital observables constrains the component <masses> and tests <general relativity>.<Binary Pulsars and Relativistic Gravity by Joseph Hooton Taylor Jr.>[Section III, Model Fitting: relativistic time transformation and post-Keplerian timing parameters]{ref}
Back to article page
