Lense-thirring precession of radio pulsars

Abstract

It is shown that if neutron stars contain dynamically de-coupled components, most plausibly discrete superfluid zones, then it is possible for the spin axes of these components o become slightly misaligned with respect to the crustal spin following a series of glitches. The crust will then undergo Lense-Thirring precession about the total angular moment with a period of ∼ 6–7.5P (assuming a crustal superfluid) and ∼ 3–6P (if the core superfluid is not tightly coupled to the crust). The precise precessional period is diagnostic of the mass distribution within each component. The implications of recent observational inferences concerning glitching pulsars are discussed. The conditions necessary for precession to be observable are analysed phenomenologically and a search of pulse-timing data for evidence of a Lense-Thirring modulation within the period range ∼ 3–8P is proposed.