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 , \dot { \mbox { $P _ { b } $ } } , determined at the 1.5 \% level of precision ( D _ { k } = 157.0 \pm 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 \dot { \mbox { $P _ { b } $ } } allows a limit on the variation of Newton ’ s gravitational constant , | \dot { G } / G| \leq 23 \times 10 ^ { -12 } yr ^ { -1 } .
We also constrain any anomalous acceleration along the line of sight to the pulsar to |a _ { \odot } / c| \leq 1.5 \times 10 ^ { -18 } s ^ { -1 } at 95 \% confidence , and derive a pulsar mass , m _ { psr } = 1.76 \pm 0.20 M _ { \odot } , one of the highest estimates so far obtained .