Evolution of the long-period pulsar GLEAM-X J162759.5–523504.3

ABSTRACT The long-period (P = 1091 s) of the recently discovered pulsar GLEAM-X J162759.5–523504.3 can be attained by neutron stars evolving with fallback discs and magnetic dipole moments a few 1030 G cm3 at ages greater than ?2 × 105 yr consistently observational upper limits to period derivative, $\dot{P}$, X-ray luminosity, LX, source. current for $\dot{P}$ allow two alternative present states: (1) disc is still active ongoing accretion low rate such that luminosity much less star’s cooling which in turn below limit LX. In this scenario, spin-down will continue $\dot{P}\sim 10^{-10}$ s s?1 until becomes inactive; final P ? 103 s. (2) already inactive, there no accretion. case, evolution has levelled off observed value range. remaining, very weak, torque sustains asymptotic 4 \times 10^{-18}$ s?1. Long periods were predicted states soft gamma repeaters anomalous pulsars relatively strong fields earlier work model.