2014/03/31 by R. De Pietri, Roberto De Pietri, Alessandra Feo +2 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Adiabatic process #Astrophysics #BETA (programming language) #Equation of state #Gamma-ray bursts and supernovae #General relativity #High-pressure geophysics and materials #Instability #Mathematical physics #Neutron star #Physics #Polytropic process #Pulsars and Gravitational Waves Research #Quantum mechanics #astro-ph.HE #gr-qc
paper · pdf · doi:10.1103/physrevd.90.024034
published as Phys. Rev. D 90, 024034 (2014) · 16 pages, 16 figures
arxiv created 2014/06/15 · openalex publication_date 2014/07/11 · arxiv updated 2014/07/16 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present results about the effect of the use of a stiffer equation of state, namely the ideal-fluid \mathrm\ensuremathΓ=2.75 one, on the dynamical bar-mode instability in rapidly rotating polytropic models of neutron stars in full general relativity. We determine the change on the critical value of the instability parameter \ensuremathβ for the emergence of the instability when the adiabatic index \mathrm\ensuremathΓ is changed from 2 to 2.75 in order to mimic the behavior of a realistic equation of state. In particular, we show that the threshold for the onset of the bar-mode instability is reduced by this change in the stiffness and give a precise quantification of the change in value of the critical parameter \ensuremathβc. We also extend the analysis to lower values of \ensuremathβ and show that low-beta shear instabilities are present also in the case of matter described by a simple polytropic equation of state.