Can the Pioneer anomaly be of gravitational origin? An observational answer

by Lorenzo Iorio (Bari University)

Thursday 14 Dec 2006, 16:00 → 17:15 Europe/Brussels

E349

In order to satisfy the equivalence principle, any mechanism proposed to gravitationally explain the Pioneer anomaly, in the form in which it is presently known from the so-far analyzed Pioneer 10/11 data, cannot leave out of consideration its impact on the motion of the planets of the Solar System as well, especially those orbiting in the regions in which the anomalous behavior of the Pioneer probes manifested itself. In this paper we, first, use the latest determinations of the secular perihelion advances of some planets in order to put on the test two gravitational mechanisms recently proposed to accommodate the Pioneer anomaly based on two models of modified gravity. Second, we use the radio-technical ranging data to Voyager 2 when it encountered Uranus and Neptune to perform a further, independent test of the hypothesis that a Pioneer-like acceleration can also affect the motion of the outer planets of the Solar System. As in the case of previous tests based on the use of the directly observable planetary right ascension and declination, the obtained answer is negative. http://arxiv.org/abs/gr-qc/0610050