Stability of coalescing binary stars against gravitational collapse: Hydrodynamical simulations

Masaru Shibata, Thomas W. Baumgarte, Stuart L. Shapiro

Research output: Contribution to journalArticle

Abstract

We perform simulations of relativistic binary stars in post-Newtonian gravity to investigate their dynamical stability prior to merger against gravitational collapse in a tidal field. In general, our equations are only strictly accurate to first post-Newtonian order, but they recover full general relativity for spherical, static stars. We study both corotational and irrotational binary configurations of identical stars in circular orbits. We adopt a soft, adiabatic equation of state with Γ = 1.4, for which the onset of instability occurs at a sufficiently small value of the compaction MIR that a post-Newtonian approximation is quite accurate. For such a soft equation of state there is no innermost stable circular orbit, so that we can study arbitrarily close binaries. This choice still allows us to study all the qualitative features exhibited by any adiabatic equation of state regarding stability against gravitational collapse. We demonstrate that, independent of the internal stellar velocity profile, the tidal field from a binary companion stabilizes a star against gravitational collapse.

Original languageEnglish (US)
Article number023002
Pages (from-to)230021+2300211
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume58
Issue number2
StatePublished - Jul 15 1998

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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