Journal Article

Hydrostatic equilibrium of causally consistent and dynamically stable neutron star models

P. S. Negi

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 388, issue 3, pages 1161-1170
Published in print August 2008 | ISSN: 0035-8711
Published online July 2008 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2008.13354.x
Hydrostatic equilibrium of causally consistent and dynamically stable neutron star models

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We show that the mass–radius (MR) relation corresponding to the stiffest equation of state (EOS) does not provide the necessary and sufficient condition of dynamical stability for equilibrium configurations, because such configurations cannot satisfy the ‘compatibility criterion’. In this regard, we construct sequences composed of core–envelope models such that, like the central condition belonging to the stiffest EOS, each member of these sequences satisfies the extreme case of the causality condition, v=c= 1, at the centre. We thereafter show that the MR relation corresponding to the said core–envelope model sequences can provide the necessary and sufficient condition of dynamical stability only when the ‘compatibility criterion’ for these sequences is ‘appropriately’ satisfied. However, the ‘compatibility criterion’ can remain satisfied even when the MR relation does not provide the necessary and sufficient condition of dynamical stability for the equilibrium configurations. In continuation of the results of a previous study, these results explicitly show that the ‘compatibility criterion’independently provides, in general, the necessary and sufficient condition of hydrostatic equilibrium for any regular sequence. In addition to its fundamental result, this study can explain simultaneously the higher and the lower values of the glitch healing parameter observed for the Crab-like and Vela-like pulsars respectively, on the basis of the starquake model of glitch generation.

Keywords: dense matter; equation of state; stars: neutron; pulsars: individual: Crab; pulsars: individual: Vela

Journal Article.  7796 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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