Equilibrium sequences of synchronized and irrotational binary systems composed of different mass stars in Newtonian gravity

Abstract

We study equilibrium sequences of close binary systems on circular orbits and composed of different mass stars with polytropic equation of state in Newtonian gravity. The solving method is a multidomain spectral method which we have recently developed. The computations are performed for both cases of synchronized and irrotational binary systems with adiabatic indices $\gamma =3,2.5,2.25,2$ and 1.8, and for three mass ratios: $M_1/M_2=0.5,0.2$ and 0.1. It is found that the equilibrium sequences always terminate at a mass shedding limit (appearance of a cusp on the surface of the less massive star). For synchronized binaries, this contrasts with the equal mass case, where the sequences terminate instead by a contact configuration. Regarding the turning point of the total angular momentum (or total energy) along a sequence, we find that it is difficult to get it for small mass ratios. Indeed, we do not find any turning points for $M_1/M_2\le 0.5$ in the irrotational case. However, in the synchronized case, it becomes easier again to find one for mass ratios much smaller than $M_1/M_2\sim 0.2$.

22 pages, 6 tables, 24 figures, revtex, Suppressed much of Sec.II, added some explanations and modified some figures, accepted for publication in Phys. Rev. D

References in corpus (2)

• Binary and Millisecond Pulsars at the New Millennium
• Quasiequilibrium sequences of synchronized and irrotational binary neutron stars in general relativity. II. Newtonian limits

Cited by in corpus (15)

• Accurate evolutions of inspiralling neutron-star binaries: prompt and delayed collapse to black hole
• Spectral Methods for Numerical Relativity
• Quasiequilibrium sequences of synchronized and irrotational binary neutron stars in general relativity. III. Identical and different mass stars with gamma=2
• A new public code for initial data of unequal-mass, spinning compact-object binaries
• Measuring Neutron Star Radii with Gravitational Wave Detectors
• Various features of quasiequilibrium sequences of binary neutron stars in general relativity
• Black hole-neutron star binaries in general relativity: effects of neutron star spin
• Second release of the CoRe database of binary neutron star merger waveforms
• Impact of the nuclear equation of state on the last orbits of binary neutron stars
• Non-conformally flat initial data for binary compact objects
• Mergers of Irrotational Neutron Star Binaries in Conformally Flat Gravity
• Binary Neutron Stars in Quasi-equilibrium
• Last orbits of binary strange quark stars
• Revealing Phase Transition in Dense Matter with Gravitational Wave Spectroscopy of Binary Neutron Star Mergers
• Tidally distorted barytropes and their Roche limits, with application to WASP-12b