Attempts to dynamically constrain the quadrupole mass moment of the millisecond pulsar PSR J1909-3744

In this paper we try to dynamically constrain the quadrupole mass moment Q of the binary millisecond pulsar PSR J1909-3744, which has a white dwarf as companion, from deviations of the third Kepler law. By determining the pulsar’s mass mp from the general relativistic expression of the phenomenologically determined post-Keplerian parameter s, we get Q = (−0.1 ± 1.3) × 10 kg m which is compatible with zero and with the values found in literature. Instead, for mp = (1.34± 0.5)M⊙, which is incompatible with general relativity by hundreds of sigma, Q would assume values incompatible with zero at 1-2.6 sigma, but largely different from the commonly accepted figures for it.