SIMBAD references

PSR B1310+18A is a 33 ms binary pulsar in a 256 day, low eccentricity orbit with a low-mass companion located in NGC 5024 (M53). In this Letter, we present the first phase-coherent timing solution for this pulsar (designated as M53A) derived from a 35 yr timing baseline; this combines the archival Arecibo Observatory data with the recent observations from the Five-hundred-meter Aperture Spherical radio Telescope. We find that the spin period derivative of the pulsar is between 6.1 and 7.5 × 10^–19 s s^–1, which implies a characteristic age between 0.70 and 0.85 Gyr. The timing solution also includes a precise position and proper motion for the pulsar, enabling the identification of the companion of M53A in Hubble Space Telescope data as a helium white dwarf (He WD) with a mass of ${M}_{{\rm{WD}}}=0.3{9}_{-0.07}^{+0.05}\,{M}_{\odot }$ and a cooling age of $0.1{4}_{-0.03}^{+0.04}\,{\rm{Gyr}}$, confirming that the system formed recently in the history of the globular cluster. The system resembles, in its spin and orbital characteristics, similarly wide pulsar-He WD systems in the Galactic disk. We conclude by discussing the origin of slow pulsars in globular clusters, showing that none of the slow pulsars in low-density globular clusters are as young as the systems observed in the densest known globular clusters.