J 0437 − 4715 : an accurate pulsar distance , a high pulsar mass and a limit on the variation of Newton ’ s gravitational constant

Analysis of ten years of high-precision timing data on the millisecond pulsar PSR J0437−4715 has resulted in a model-independent kinematic distance based on an apparent orbital period derivative, Ṗb, determined at the 1.5% level of precision (Dk = 157.0±2.4 pc), making it one of the most accurate stellar distance estimates published to date. The discrepancy between this measurement and a previously published parallax distance estimate is attributed to errors in the DE200 Solar System ephemerides. The precise measurement of Ṗb allows a limit on the variation of Newton’s gravitational constant, |Ġ/G| ≤ 23×10 yr. We also constrain any anomalous acceleration along the line of sight to the pulsar to |a⊙/c| ≤ 1.5× 10 −18 s at 95% confidence, and derive a pulsar mass, mpsr = 1.76± 0.20M⊙, one of the highest estimates so far obtained. Subject headings: stars: distances — pulsars: individual (PSR J0437−4715) — stars: neutron