Geodesy and Geophysics Working Group

Primary Questions

  • What is the thickness and density of the crust?

  • What has shaped the surface of Mercury?

  • What are the relative roles of tectonism, volcanism and impacts with respect to Mercury’s surface?

  • How strong was the contraction and when did it occur?

  • What are the regions in the southern hemisphere that present crustal magnetization?

  • What is the structure and rheology (i.e, viscosity, rigidity) of the mantle?

  • What is the size, density and physical state (liquid, solid) of the core?

  • What is the relative amount of volatiles in the core?

  • What is Mercury’s deviation from hydrostatic state?

  • What is the level of precision of Einstein’s theory of General Relativity?

  • Are any violations of the Strong Equivalence Principle (SEP) in the weak-field?

  • How does the solar inter- nal evolution affect planetary ephemerides?

  • How and when did Mercury get captured in the 3:2 spin-orbit resonance?

Science Objectives

  • Local and global mapping of gravity and topographic relief
  • Local and global measurements of the magnetic field
  • Accurate global determination of Mercury’s degree 2 shape and gravity
  • Gravitational and surface tides measured by the Love numbers k2 and h2, including phase lags.
  • Polar moment of inertia of the outer layers (crust and mantle) by measuring librations with altimetric data.

  • Internal magnetic field magnitude and structure (i.e., dipole and equatorial offset)

  • Accurate measure of the offset between the center of mass and the center of figure

  • Mercury rotation from altimetry and orbital period from radio science

  • Parameterized PostNewtonian (PPN) γ, β,  α1, and α2. Nordvedt's parameter η.

  • Sun’s J2, and GM and its temporal variation due to solar mass loss rate.

Meetings (most recent first)

Virtual Meetings: 

1st GGWG virtual meeting on Friday 18 June. Two science talks: 

  • Jurrien S. Knibbe, "Mercury's Interior Structure Constrained by Density and P-Wave Velocity Measurements of Liquid Fe-Si-C Alloys"

  • Gregor Steinbrügge "Challenges on Mercury's Interior Structure Posed by the New Measurements of its Obliquity and Tides"

and findal discussion.

 

Resources

Meetings

  • Next GGWG virtual meeting will be on September 24.

Working Group Chair

  • Hauke Hussmann
  • Antonio Genova

Other Information