Get access
Journal of Geophysical Research: Planets

The tides of Mercury and possible implications for its interior structure

Authors

  • Sebastiano Padovan,

    Corresponding author
    1. Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, California, USA
    Search for more papers by this author
  • Jean-Luc Margot,

    1. Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, California, USA
    2. Department of Physics and Astronomy, University of California, Los Angeles, California, USA
    Search for more papers by this author
  • Steven A. Hauck II,

    1. Department of Earth, Environmental, and Planetary Sciences, Case Western Reserve University, Cleveland, Ohio, USA
    Search for more papers by this author
  • William B. Moore,

    1. Department of Atmospheric and Planetary Sciences, Hampton University, Hampton, Virginia, USA
    2. National Institute of Aerospace, Hampton, Virginia, USA
    Search for more papers by this author
  • Sean C. Solomon

    1. Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA
    2. Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, District of Columbia, USA
    Search for more papers by this author

Abstract

The combination of the radio tracking of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft and Earth-based radar measurements of the planet's spin state gives three fundamental quantities for the determination of the interior structure of Mercury: mean density ρ, moment of inertia C, and moment of inertia of the outer solid shell Cm. This work focuses on the additional information that can be gained by a determination of the change in gravitational potential due to planetary tides, as parameterized by the tidal potential Love number k2. We investigate the tidal response for sets of interior models that are compatible with the available constraints (ρ, C, and Cm). We show that the tidal response correlates with the size of the liquid core and the mean density of material below the outer solid shell and that it is affected by the rheology of the outer solid shell of the planet, which depends on its temperature and mineralogy. For a mantle grain size of 1 cm, we calculate that the tidal k2 of Mercury is in the range 0.45 to 0.52. Some of the current models for the interior structure of Mercury are compatible with the existence of a solid FeS layer at the top of the core. Such a layer, if present, would increase the tidal response of the planet.

Get access to the full text of this article

Ancillary