2007MNRAS.376.1727I

In this paper, we directly constrain possible spatial variations of the Newtonian gravitational constant G over the range ~0.01-5 au in various extrasolar multiplanet systems. Using the third Kepler law, we determine the quantity Γ_XY= G_X/G_Y for each couple of planets X and Y located at different distances from their parent star; deviations of the measured values of Γ from unity would signal variations of G. The obtained results for η = 1 - Γ are found to be very compatible with zero within the experimental errors (η/δη ~ 0.2-0.3). We make a comparison with an analogous test previously performed in our Solar system.