POST-NEWTONIAN EXPANSION OF GRAVITATIONAL-WAVES FROM A COMPACT STAR ORBITING A ROTATING BLACK-HOLE IN BRANS-DICKE THEORY - CIRCULAR ORBIT CASE

In the context of Brans-Dicke theory, we calculate the post-Newtonian expansion of the scalar part of gravitational radiation from a compact star in a circular orbit around a rotating black hole up to O(v(5)) b eyond the leading, Newtonian-dipole formula. The calculation is based on a method developed recently by Sasaki in the Schwarzschild case in the context of general relativity. The orbit of a compact star is rest ricted on the equatorial plane. Then we estimate the post-Newtonian ef fect of scalar radiation to the orbital evolution of coalescing compac t binaries. We find that the post-Newtonian effect of scalar radiation is small in the LIGO band if we take into account the experimental bo und of the Brans-Dicke parameter omega(BD)>500. On the other hand, we find that the post-Newtonian effect of the scalar radiation is not neg ligible for the LISA experiment.