کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1774758 | 1021173 | 2009 | 13 صفحه PDF | دانلود رایگان |
We study the orbital behavior of Saturn’s satellites Enceladus and Dione during their passage through the 2:1 mean-motion resonances to constrain their interior structures, parameterized by the quantity k2/Qk2/Q (assumed constant). Enceladus’ evolution after escape from the second-order e-Enceladus e -Dione resonance requires that (k2/Q)Enceladus<8×10-4(k2/Q)Enceladus<8×10-4, for that QSaturn>18,000QSaturn>18,000. This result is in agreement with [Meyer, J., Wisdom, J., 2008b. Icarus 193, 213–223]. The present-day libration amplitude of Enceladus requires that (k2/Q)Enceladus>1.2×10-4(k2/Q)Enceladus>1.2×10-4, assuming that QSaturn<105QSaturn<105. Dione’s present-day eccentricity indicates that (k2/Q)Dione⩽3×10-4(k2/Q)Dione⩽3×10-4 for QSaturn>18,000QSaturn>18,000. Assuming Maxwellian viscoelastic behavior, we find that for Enceladus a convective ice shell overlying an ocean is too dissipative to match the orbital constraints. We conclude that a conductive shell overlying an ocean is more likely, and discuss the implications of this result. Dione’s ice shell is also likely to be conductive, but our results are less constraining.
Journal: Icarus - Volume 204, Issue 2, December 2009, Pages 597–609