The effects of core-mantle gravitational coupling on the rotational dynamics of Mercury

• Author / Creator

  Veasey, Martin James

• As Mercury orbits the Sun, solar induced gravitational torques give rise to a planetary libration. While undergoing this 88 day period libration, the axes of minimum moment of inertia of the mantle and solid core, if present, become misaligned, leading to a gravitational torque which initiates a free-mode of axial oscillation between the inner core and mantle. For a large gravitational torque, the free-mode period approaches the period of the libration forcing, and should participate in the planet’s libration response. The goal of this work is to determine whether Mercury’s observed librations can be used to place constraints on the inner core structure. Perturbations in Mercury’s rotation rate are simulated for a range of interior structures. For models where the free-mode interferes with the libration signature, a marginally better fit between model response and observations is obtained, compared to models which exhibit the libration signature alone.

• Subjects / Keywords

  • Rotation
  • Mercury
  • Couping

• Graduation date

  Fall 2010

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3MD77

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.