PSR J1755-2550: a young radio pulsar with a massive, compact companion
Abstract
Radio pulsars found in binary systems with short orbital periods are usually fast spinning as a consequence of recycling via mass transfer from their companion stars; this process is also thought to decrease the magnetic field of the neutron star being recycled. Here, we report on timing observations of the recently discovered binary PSR J1755-2550 and find that this pulsar is an exception: with a characteristic age of 2.1 Myr, it is relatively young; furthermore, with a spin period of 315 ms and a surface magnetic field strength at its poles of 0.88 × 1012 G, the pulsar shows no sign of having been recycled. Based on its timing and orbital characteristics, the pulsar either has a massive white dwarf (WD) or a neutron star (NS) companion. To distinguish between these two cases, we searched radio observations for a potential recycled pulsar companion and analysed archival optical data for a potential WD companion. Neither work returned conclusive detections. We apply population synthesis modelling and find that both solutions are roughly equally probable. Our population synthesis also predicts a minimum mass of 0.90 M⊙ for the companion star to PSR J1755-2550 and we simulate the systemic runaway velocities for the resulting WDNS systems which may merge and possibly produce Ca-rich supernovae. Whether PSR J1755-2550 hosts a WD or a NS companion star, it is certainly a member of a rare subpopulation of binary radio pulsars.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2018
- DOI:
- 10.1093/mnras/sty482
- arXiv:
- arXiv:1802.08248
- Bibcode:
- 2018MNRAS.476.4315N
- Keywords:
-
- stars: neutron;
- pulsars: general;
- pulsars: individual: PSR J1755-2550;
- white dwarfs;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 13 pages, 11 figures, accepted by MNRAS