Speaker
Description
The 500 m Precision Floor in Neutron Star Radius Measurements
abstract. Multi-messenger observations of neutron stars aim to constrain the dense-matter equation of state via mass-radius measurements. We demonstrate that, for a canonical 1.4 M star, current crust-modeling uncertainties impose a persistent∼500 m precision floor in radius predictions. This threshold is comparable to—and in some cases exceeds—the radius differences predicted for quark-hadron transitions, hyperonic cores, dark matter admixture, and modified gravity. Consequently, in the one-dimensional mass-radius plane, these scenarios remain effectively degenerate. Breaking this degeneracy requires either reducing crustal uncertainties to σR ≪500 m—a challenge for current missions—or shifting toward multi-observable tomography. The 500 m precision floor thus reframes the inverse problem, motivating a move beyond radius measurements alone.