Timing of a young mildly recycled pulsar with a massive white dwarf companion

Abstract

We report on timing observations of the recently discovered binary pulsar PSR J1952+2630using the Arecibo Observatory. The mildly recycled 20.7-ms pulsar is in a 9.4-h orbit witha massive, MWD 0.93M⊙, white dwarf (WD) companion. We present, for the first time,a phase-coherent timing solution, with precise spin, astrometric and Keplerian orbital parameters.This shows that the characteristic age of PSR J1952+2630 is 77 Myr, youngerby one order of magnitude than any other recycled pulsar-massive WD system. We derivean upper limit on the true age of the system of 150 Myr. We investigate the formation ofPSR J1952+2630 using detailed modelling of the mass-transfer process from a naked heliumstar on to the neutron star following a common-envelope phase (CaseBBRoche lobe overflow).From our modelling of the progenitor system, we constrain the accretion efficiency of the neutronstar, which suggests a value between 100 and 300 per cent of the Eddington accretion limit.We present numerical models of the chemical structure of a possible oxygen-neon-magnesiumWD companion. Furthermore, we calculate the past and the future spin evolution of PSR J1952+2630, until the system merges in about 3.4 Gyr due to gravitational wave emission.Although we detect no relativistic effects in our timing analysis, we show that severalsuch effects will become measurable with continued observations over the next 10 yr; thus, PSR J1952+2630 has potential as a testbed for gravitational theories. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.