2026ApJ...996..101R

We report on new orbit-minimum photometry and revised radial-velocity fitting that provide an improved measurement of the mass of the neutron star (NS) in pulsar PSR J0952-0607 at M_NS = 2.35 ± 0.11 M_⊙. With its fast spin and unusually low magnetic field, this NS has evidently experienced unusual evolution, likely connected with its high mass, which is now 2.5σ above that of the heaviest pulsar with a white dwarf companion, as measured by Shapiro delay techniques. By tightening the mass measurement, we also raise the maximum (commonly called Tolman-Oppenheimer-Volkoff) NS mass to M_TOV > 2.27 M_⊙ (2.12 M_⊙) at 1σ (3σ) confidence, which improves bounds on the dense-matter equation of state. While the statistical error decreases and systematic issues should be modest, uncertainties remain; we comment briefly on these factors and prospects for further improvement.