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Oblateness effects on the spindown of fast pulsars


The recent discovery1,2 of the very rapidly rotating pulsar PSR1937+214 has triggered off many theoretical speculations3–5. Assuming that the pulsar is a fast-rotating superdense fluid, we show here that the increase in the moment of inertia and in the gravitational self-energy of the spheroid due to its oblateness lead to substantial differences in the time evolution of the pulsar from that predicted by the standard models. Careful observations of its , and its spectrum can put constraints on the properties of neutron star matter. Even with the existing observation of P = 1.56 ms, considerations of dynamical stability of the rapidly rotating neutron star yield a lower limit ρ¯>1.7×1014 g cm−3 for the mean stellar density.

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Cowsik, R., Ghosh, P. & Melvin, M. Oblateness effects on the spindown of fast pulsars. Nature 303, 308–310 (1983).

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