Solar system expansion and strong equivalence principle as seen by the NASA MESSENGER mission.

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 ??=?(-6.6?±?7.2)?×?10-5. By assuming a metric theory of gravitation, we retrieved the post-Newtonian parameter ??=?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.

SUBMITTER: Genova A 

PROVIDER: S-EPMC5773540 | biostudies-other | 2018 Jan

REPOSITORIES: biostudies-other