Universal relations for differentially rotating relativistic stars at the threshold to collapse

Abstract

A binary neutron star merger produces a rapidly and differentially rotating compact remnant whose lifespan heavily affects the electromagnetic and gravitational emissions. Its stability depends on both the equation of state (EOS) and the rotation law and it is usually investigated through numerical simulations. Nevertheless, by means of a sufficient criterion for secular instability, equilibrium sequences can be used as a computationally inexpensive way to estimate the onset of dynamical instability, which, in general, is close to the secular one. This method works well for uniform rotation and relies on the location of turning points: stellar models that are stationary points in a sequence of equilibrium solutions with constant rest mass or angular momentum. Here, we investigate differentially rotating models (using a large number of equations of state and different rotation laws) and find that several universal relations between properly scaled gravitational mass, rest mass and angular momentum of the turning-point models that are valid for uniform rotation, are insensitive to the degree of differential rotation, to high accuracy.

8 pages, 8 figures, submitted to MNRAS

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Cited by in corpus (7)

• On the stability and maximum mass of differentially rotating relativistic stars
• Flares, jets and quasi-periodic outbursts from neutron star merger remnants
• Equilibrium sequences of differentially rotating stars with post-merger-like rotational profiles
• Revisiting the maximum mass of differentially rotating neutron stars in general relativity: Übermassive stars with realistic equations of state
• New quasi-universal relations for static and rapid rotating neutron stars
• Universal behavior of compact star based upon gravitational binding energy
• Maximum Mass Of Differentially Rotating Strange Quark Stars