Solar system expansion and strong equivalence principle as seen by the NASA MESSENGER mission.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29348613.
- Also identified by DOI 10.1038/s41467-017-02558-1 and PMC identifier 5773540.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The NASA MESSENGER mission explored the innermost planet of the solar system and obtained a rich data set of range measurements for the determination of Mercury's ephemeris. Here we use these precise data collected over 7 years to estimate parameters related to general relativity and the evolution of the Sun. These results confirm the validity of the strong equivalence principle with a significantly refined uncertainty of the Nordtvedt parameter η = (-6.6 ± 7.2) × 10-5. By assuming a metric theory of gravitation, we retrieved the post-Newtonian parameter β = 1 + (-1.6 ± 1.8) × 10-5 and the Sun's gravitational oblateness, [Formula: see text] = (2.246 ± 0.022) × 10-7. Finally, we obtain an estimate of the time variation of the Sun gravitational parameter, [Formula: see text] = (-6.13 ± 1.47) × 10-14, which is consistent with the expected solar mass loss due to the solar wind and interior processes. This measurement allows us to constrain [Formula: see text] to be <4 × 10-14 per year.