open access

https://hdl.handle.net/2115/64393

Tidal deformation of Ganymede: Sensitivity of Love numbers on the interior structure

英語

2016-07-28

American Geophysical Union

Journal of Geophysical Research: Planets

121(7)

1362-1375

Tidal deformation of icy satellites provides crucial information on their subsurface structures. In this study, we investigate the parameter dependence of the tidal displacement and potential Love numbers (i.e., h(2) and k(2), respectively) of Ganymede. Our results indicate that Love numbers for Ganymede models without a subsurface ocean are not necessarily smaller than those with a subsurface ocean. The phase lag, however, depends primarily on the presence/absence of a subsurface ocean. Thus, the determination of the phase lag would be of importance to infer whether Ganymede possesses a subsurface ocean or not based only on geodetic measurements. Our results also indicate that the major control on Love numbers is the thickness of the ice shell if Ganymede possesses a subsurface ocean. This result, however, does not necessarily indicate that measurement of either of h(2) or k(2) alone is sufficient to estimate the shell thickness; while a thin shell leads to large h(2) and k(2) independent of parameters, a thick shell does not necessarily lead to small h(2) and k(2). We found that to reduce the uncertainty in the shell thickness, constraining k(2) in addition to h(2) is necessary, highlighting the importance of collaborative analyses of topography and gravity field data.

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© 2016 American Geophysical Union

2169-9097