Rotating Black Holes and the Density Cap: Spin Dependence of the Capped Core's Horizon Fraction

At zero spin the capped radius is a fraction 2.667e-14 of the horizon radius. At a spin parameter of 0.998 the horizon has contracted to 1.570e+04 metres and the fraction rises to 5.016e-14, nearly doubling, while the equatorial static limit stays at 2.953e+04 metres and the core itself remains at 7.876e-10 metres. Rotation therefore brings the cap proportionally closer to the horizon but nowhere near it: even at the practical spin ceiling the core sits more than thirteen orders of magnitude inside the horizon. The conclusion disciplines speculation about spin-exposed cores. Computed from stated assumptions, not measured.