HR: 0800h
AN: P41A-0193    [Abstracts]
TI: Tidally Induced Core Dynamo of Mars
AU: * Arkani-Hamed, J
EM: jafar@physics.utoronto.ca
AF: Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 1A7, Canada
AU: Seyed-Mahmoud, B
EM: seyeb0@uleth.ca
AF: Physics Department, University of Lethbridge, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
AU: Aldridge, K
EM: keith@yorku.ca
AF: Graduate Program in Earth and Space Science, York University, Toronto, ON M3J 1P3, Canada
AB: We study tidal excitation of elliptical instability inside the liquid core of Mars by an asteroid similar to one that created Hellas basin. The growth time of the excitation is 5,000 -20,000 years when the asteroid is at a distance of 35,000 – 50,000 km. We investigate the spin-orbit coupling of the asteroid and Mars through their tidal interaction. An captured prograde asteroid can excite the elliptical instability of the Martian core for only a few million years before colliding with Mars, whereas a captured retrograde asteroid can excite the elliptical instability for hundreds of millions of years before colliding on Mars. The tidal energy dissipation rate is over two orders of magnitude greater than the magnetic energy dissipation rate. Our results indicate that a retrograde Hellas-type asteroid is quite capable of exciting the elliptical instability in the Martian core, thus providing a candidate process to drive a core dynamo
DE: 5440 Magnetic fields and magnetism
DE: 5450 Orbital and rotational dynamics (1221)
DE: 5499 General or miscellaneous
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting