2013/09/30 by Brynmor Haskell, B. Haskell, R. Ciolfi +4 · 119 citations
Earth and Planetary Sciences · Engineering · Physics and Astronomy · #Astronomy #Astrophysics #Condensed matter physics #Geophysics and Gravity Measurements #Geophysics and Sensor Technology #Neutron star #Physics #Pulsars and Gravitational Waves Research #Stars #Universality (dynamical systems) #astro-ph.SR #gr-qc
paper · pdf · doi:10.1093/mnrasl/slt161
published in Monthly Notices of the Royal Astronomical Society Letters 438(1), L71-L75 (Oxford University Press) · Published as MNRAS Letters 438, L71-L75 (2014)
openalex publication_date 2013/11/01 · arxiv created 2014/01/29 · arxiv updated 2014/06/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Abstract Recently, general relations among the quadrupole moment (Q), the moment of inertia (I) and the tidal deformability (Love number) of a neutron star were shown to exist. They are nearly independent of the nuclear matter equation of state and would be of great aid in extracting parameters from observed gravitational waves and in testing general relativity. These relations, however, do not account for strong magnetic fields. We consider this problem by studying the effect of a strong magnetic field on slowly rotating relativistic neutron stars and show that, for simple magnetic field configurations that are purely poloidal or purely toroidal, the relation between Q and I is again nearly universal. However, different magnetic field geometries lead to different I–Q relations, and, in the case of a more realistic twisted-torus magnetic field configuration, the relation depends significantly on the equation of state, losing its universality. I–Love–Q relations must thus be used with very great care, since universality is lost for stars with long spin periods, i.e. P ≳ 10 s, and strong magnetic fields, i.e. B ≳ 1012 G.