Gravitomagnetism and the Earth-Mercury range

TL;DR

This paper investigates the impact of the Sun's gravitomagnetic field on the Earth-Mercury range, highlighting the potential for future laser ranging to detect relativistic effects amidst other gravitational influences.

Contribution

It provides a numerical analysis of the Lense-Thirring effect on Earth-Mercury distance and assesses systematic errors from other gravitational sources for upcoming measurement missions.

Findings

Lense-Thirring effect causes a 17.5-meter variation over 2 years.

Future laser ranging can potentially detect this relativistic signal.

Other gravitational effects can introduce larger systematic errors, but with different temporal patterns.

Abstract

We numerically work out the impact of the general relativistic Lense-Thirring effect on the Earth-Mercury range caused by the gravitomagnetic field of the rotating Sun. The peak-to peak nominal amplitude of the resulting time-varying signal amounts to 1.75 10^1 m over a temporal interval 2 yr. Future interplanetary laser ranging facilities should reach a cm-level in ranging to Mercury over comparable timescales; for example, the BepiColombo mission, to be launched in 2014, should reach a 4.5 - 10 cm level over 1 - 8 yr. We looked also at other Newtonian (solar quadrupole mass moment, ring of the minor asteroids, Ceres, Pallas, Vesta, Trans-Neptunian Objects) and post-Newtonian (gravitoelectric Schwarzschild solar field) dynamical effects on the Earth-Mercury range. They act as sources of systematic errors for the Lense-Thirring signal which, in turn, if not properly modeled, may bias the recovery of some key parameters of such other dynamical features of motion. Their nominal peak-to-peak amplitudes are as large as 4 10^5 m (Schwarzschild), 3 10^2 m (Sun's quadrupole), 8 10^1 m (Ceres, Pallas, Vesta), 4 m (ring of minor asteroids), 8 10^-1 m (Trans-Neptunian Objects). Their temporal patterns are different with respect to that of the gravitomagnetic signal.