= Equal-mass circular-binary quadrupole luminosity
{title2=$P=\frac{2G^4M^5}{5c^5R^5}$}
For two masses $M$ at opposite points of a circular orbit, each at radius $R$ from the centre of mass, $\Omega^2=GM/(4R^3)$. The trace-free <mass quadrupole moment> oscillates at twice the orbital frequency, and its third-derivative squared contraction is $128M^2R^4\Omega^6$. The <quadrupole formula> gives the displayed phase-independent luminosity. Using separation $2R$ rather than individual radius $R$ avoids a factor-of-32 error.
Back to article page
