Open AccessGeophysical implications of the long‐wavelength topography of Rhea
Author(s) -
Nimmo F.,
Bills B. G.,
Thomas P. C.,
Asmar S. W.
Publication year - 2010
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010je003604
Subject(s) - lithosphere , geology , radiogenic nuclide , wavelength , geophysics , geodesy , degree (music) , seismology , mantle (geology) , physics , optics , tectonics , acoustics
We use limb profiles to investigate the long‐wavelength topography and topographic variance spectrum of Rhea. One‐dimensional variance spectra show a break in slope at a wavelength of ≈300 km; a similar effect is seen on the Moon and may be a signature of an elastic lithosphere having a thickness T e ≈ 10 km. The implied heat flux is ∼15 mW m −2 , much higher than can be explained by radiogenic heating. We use the 1‐D spectral behavior to constrain our solution for the long‐wavelength global topography of Rhea. The degree 3 topography is large enough, if uncompensated, to contaminate estimates of the degree 2 gravity using existing flyby data. Current models of Rhea internal structures which rely on these degree 2 estimates may thus be inaccurate, illustrating the need to acquire further Rhea gravity data.