New upper limit on the cosmological constant from solar system dynamics

Abstract

The cosmological constant Λ is the simplest model for explaining the dark energy which supposedly drives the observed accelerated expansion rate of the Universe. Together with the concept of cold dark matter, it satisfactorily accommodates a wealth of observations related to cosmology. Due to its assumed constancy throughout the Universe, Λ might also affect the dynamics of the planets in the solar system, although with extremely small effects. However, modern high-precision ephemerides provide a promising tool for constraining it. Using the supplementary advances in the perihelia provided by current INPOP10a and EPM2011 ephemerides, we obtain a new upper limit on Λ in the solar system when the Lense-Thirring effect due to the Sun's angular momentum and the uncertainty of the Sun's quadrupole moment are properly taken into account. These two factors were mostly absent in previous works dealing with Λ. We find that INPOP10a yields an upper limit of Λ = (0.26 ± 1.45) × 10−43 m−2 and EPM2011 gives Λ = (−0.44 ± 8.93) × 10−43 m−2. Such bounds are about 10 times less than previously estimated results.