The double pulsar PSR J0737-3039A/B

PHYSICS · Subjective · Fermi University Physics · Mechanics & Dynamical Systems · Relativity & Gravitation · Gravitation and central-force motion

The Geometry of Gravity, Ch Orbits and light rays in Schwarzschild spacetime

Problem

The double pulsar PSR J0737-3039A/B, two neutron stars both seen as pulsars, has total mass M=2.587 M⊙M = 2.587\,M_\odot, orbital semi-major axis a=8.79×108a = 8.79\times10^8 m, eccentricity e=0.0878e = 0.0878, and orbital period Torb=2.454T_{\rm orb} = 2.454 hours. Treating the orbit as a Schwarzschild geodesic of the reduced two-body problem with total mass MM, estimate the periastron advance in degrees per year, using Δϖ=6πGMc2a(1−e2) per orbit.\Delta\varpi = \frac{6\pi GM}{c^2 a (1-e^2)}\ {\rm per\ orbit}. Use GM⊙/c2=1.48GM_\odot/c^2 = 1.48 km and 11 year =3.156×107= 3.156\times10^7 s. Compare your estimate with the measured value of about 16.9∘16.9^\circ per year.

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