Equatorial plane circular orbits in the Taub-NUT spacetime (Q1420842)

In this paper the authors consider the (necessarily accelerated) circular orbits in the equatorial plane and their characterization in terms of the Frenet-Serret curvature and torsions. Referred to Boyer-Lindquist-like coordinates, they show that within each tangent space, the four-velocity \((t-\phi)\) plane of the family of circular orbits is orthogonal to the acceleration \((r-\theta)\) plane as in the Schwarzschild case, but now the presence of the gravitational monopole complicates matters.