Neutron star sequences and the starquake glitch model for the Crab and the Vela pulsars

We construct for the first time, the sequences of stable neutron star (NS) models capable of explaining simultaneously, the glitch healing parameters, Q, of both the pulsars, the Crab (Q ≥ 0.7) and the Vela (Q ≤ 0.2), on the basis of starquake mechanism of glitch generation. These models yield an upper bound on surface redshift of NSs, zR ≃ 0.77. If the lower limit of the observational constraint of (i) Q ≥ 0.7 for the Crab pulsar and (ii) the recently evaluated value of the moment of inertia for the Crab pulsar, ICrab,45 ≥ 3.04 (where I45 = I/10 45 g.cm), both are imposed together on these models, the models yield the value of matching density, Eb = 7.0794 × 10 g cm at the core-envelope boundary. This value of matching density yields a model-independent upper bound on neutron star masses, Mmax ≤ 2.59M⊙, and the strong lower bounds on surface redshift zR ≃ 0.6232 and mass M ≃ 2.455M⊙ for the Crab (Q ≃ 0.7) and the strong upper bound on surface redshift zR ≃ 0.2016 and mass M ≃ 1.142M⊙ for the Vela (Q ≃ 0.2) pulsar. However, for the observational constraint of the ‘central’ weighted mean value Q ≈ 0.72, and ICrab,45 > 3.04, for the Crab pulsar, the minimum surface redshift and mass of the Crab pulsar are slightly increased to the values zR ≃ 0.655 and M ≃ 2.5M⊙ respectively, whereas for the central weighted mean value Q ≈ 0.12 for the Vela pulsar, the maximum surface redshift and mass of the Vela pulsar are slightly decreased to the values zR ≃ 0.1645 and M ≃ 0.9635M⊙ respectively. These results set an upper and lower bound on the energy of a gravitationally redshifted electron-positron annihilation line in the range of about 0.309 0.315 MeV from the Crab and in the range of about 0.425 0.439 MeV from the Vela pulsar.