PSR J0952−0607: The Fastest and Heaviest Known Galactic Neutron Star

Abstract We describe Keck-telescope spectrophotometry and imaging of the companion of the “black widow” pulsar PSR J0952−0607, the fastest known spinning neutron star (NS) in the disk of the Milky Way. The companion is very faint at minimum brightness, presenting observational challenges, but we have measured multicolor light curves and obtained radial velocities over the illuminated “day” half of the orbit. The model fits indicate system inclination i = 59.°8 ± 1.°9 and a pulsar mass M NS = 2.35 ± 0.17 M ⊙ , the largest well-measured mass found to date. Modeling uncertainties are small, since the heating is not extreme; the companion lies well within its Roche lobe and a simple direct-heating model provides…

• NA
  National Aeronautics and Space Administration

  Awards: 80NSSC17K0024, 80NSSC21K0896