A Massive Pulsar in a Compact Relativistic Binary

TLDR

Many physically motivated extensions to general relativity predict substantial deviations in the properties of spacetime surrounding massive neutron stars. The high pulsar mass and the compact orbit make this system a sensitive laboratory of a previously untested strong‑field gravity regime. The 2.01 M☉ pulsar in a 2.46‑hour orbit with a 0.172 M☉ white dwarf shows orbital decay consistent with GR, reinforcing the theory under extreme conditions, supporting GR‑based gravitational‑wave templates, and tightening constraints on dense‑matter physics and binary evolution.

Abstract

Many physically motivated extensions to general relativity (GR) predict substantial deviations in the properties of spacetime surrounding massive neutron stars. We report the measurement of a 2.01 ± 0.04 solar mass (M☉) pulsar in a 2.46-hour orbit with a 0.172 ± 0.003 M☉ white dwarf. The high pulsar mass and the compact orbit make this system a sensitive laboratory of a previously untested strong-field gravity regime. Thus far, the observed orbital decay agrees with GR, supporting its validity even for the extreme conditions present in the system. The resulting constraints on deviations support the use of GR-based templates for ground-based gravitational wave detectors. Additionally, the system strengthens recent constraints on the properties of dense matter and provides insight to binary stellar astrophysics and pulsar recycling....