as tr o - ph / 9 50 90 06 1 Se p 19 95 Coalescing neutron stars

نویسنده

  • G. Schäfer
چکیده

We investigate the dynamics and evolution of coalescing neutron stars. The three-dimensional Newtonian equations of hydrodynamics are integrated by the “Piecewise Parabolic Method” on an equidistant Cartesian grid with a resolution of 643 or 1283. Although the code is purely Newtonian, we do include the emission of gravitational waves and their backreaction on the hydrodynamic flow. The properties of neutron star matter are described by the physical equation of state of Lattimer & Swesty (1991). In addition to the fundamental hydrodynamic quantities, density, momentum, and energy, we follow the time evolution of the electron density in the stellar gas. Energy loss by all types of neutrinos and changes of the electron fraction due to the emission of electron neutrinos and antineutrinos are taken into account by an elaborate “neutrino leakage scheme”. We simulate the coalescence of two identical, cool neutron stars with a baryonic mass of 1:6M and a radius of 15 km and with an initial center-to-center distance of 42 km. The initial distributions of density and electron concentration are given from a model of a cold neutron star in hydrostatic equilibrium, the temperature in our initial models is increased such that the thermal energy is about 3% of the degeneracy energy for given density and electron fraction (central temperature about 8 MeV). We investigate three cases which differ by the initial velocity distribution in the neutron stars, representing different cases of the neutron star spins relative to the direction of the orbital angular momentum vector. The orbit decays due to gravitational-wave emission, and after half a revolution the stars are so close that dynamical instability sets in. Within about 1 ms they merge into a rapidly spinning (Pspin 1 ms), high-density body ( 1014 g/cm3) with a surrounding thick disk of material with densities 101

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

ar X iv : g r - qc / 9 81 20 54 v 1 1 6 D ec 1 99 8 A Way to 3 D Numerical Relativity — Coalescing Binary Neutron Stars —

Long baseline interferometers to detect gravitational waves such as TAMA300 [1], GEO600 [2], VIRGO [3], LIGO [4] will be in operation by the end of this century or the beginning of the 21st century. One of the most important sources of gravitational waves for such detectors are coalescing binary neutron stars. PSR1913+16 is the first binary neutron stars found by Hulse and Taylor. The existence...

متن کامل

ar X iv : 0 90 4 . 41 63 v 1 [ as tr o - ph . S R ] 2 7 A pr 2 00 9 The 13 C Pocket In Low Mass AGB Stars

It is well known that thermally pulsing Asymptotic Giant Branch stars with low mass play a relevant role in the chemical evolution. They have synthesized about 30% of the galactic carbon and provide an important contribution to the nucleosynthesis of heavy elements (A>80). The relevant nucleosynthesis site is the He-rich intermediate zone (less than 10 M⊙), where α(2α, γ) C reactions and slow n...

متن کامل

ar X iv : 0 90 5 . 21 83 v 1 [ as tr o - ph . G A ] 1 3 M ay 2 00 9 Do all millisecond pulsars share a common heritage ?

The discovery of millisecond pulsations from neutron stars in low mass X-ray binary (LMXB) systems has substantiated the theoretical prediction that links millisecond radio pulsars (MSRPs) and LMXBs. Since then, the process that produces millisecond radio pulsars from LMXBs, followed by spin-down due to dipole radiation has been conceived as the ’standard evolution’ of millisecond pulsars. Howe...

متن کامل

ar X iv : g r - qc / 9 50 80 17 v 1 7 A ug 1 99 5 Gravitational waves from coalescing compact binaries ∗

This article is intended to provide a pedagogical account of issues related to, and recent work on, grav-itational waves from coalescing compact binaries (composed of neutron stars and/or black holes). These waves are the most promising for kilometer-size interferometric detectors such as LIGO and VIRGO. Topics discussed include: interferometric detectors and their noise; coalescing compact bin...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 1997