Advances in the Measurement of the Lense-Thirring Effect with Planetary Motions in the Field of the Sun

By processing more than 400 000 planetary observations of various types with the dynamical models of the EPM2006 ephemerides, E.V. Pitjeva recently estimated a correction to the canonical Newtonian-Einsteinian Venus' perihelion precession of − 0.0004 ± 0.0001 arcseconds per century. The prediction of general relativity for the Lense-Thirring precession of the perihelion of Venus is − 0.0003 arcseconds per century. It turns out that neither other mismodelled/unmodelled standard Newtonian/Einsteinian effects nor exotic ones, postulated to, for example, explain the Pioneer anomaly, may have caused the estimated extra-precession of the Venus orbit which, thus, can be reasonably attributed to the gravitomagnetic field of the Sun, not modelled in the routines of the EPM2006 ephemerides. However, it must be noted that the quoted error is the formal, statistical one; the realistic uncertainty might be larger. Future improvements of the inner planets' ephemerides, with the inclusion of the Messenger and Venus-Express tracking data, should further improve the accuracy and the consistency of such a test of general relativity which would also benefit from the independent estimation of the extra-precessions of the perihelia (and the nodes) by other teams of astronomers.