The Gravity Field and Interior Structure of Enceladus
Abstract
The small and active Saturnian moon Enceladus is one of the primary targets of the Cassini mission. We determined the quadrupole gravity field of Enceladus and its hemispherical asymmetry using Doppler data from three spacecraft flybys. Our results indicate the presence of a negative mass anomaly in the south-polar region, largely compensated by a positive subsurface anomaly compatible with the presence of a regional subsurface sea at depths of 30 to 40 kilometers and extending up to south latitudes of about 50°. The estimated values for the largest quadrupole harmonic coefficients (10^(6)J_2 = 5435.2 ± 34.9, 10^(6)C_22 = 1549.8 ± 15.6, 1σ) and their ratio (J_(2)/C_(22) = 3.51 ± 0.05) indicate that the body deviates mildly from hydrostatic equilibrium. The moment of inertia is around 0.335MR^2, where M is the mass and R is the radius, suggesting a differentiated body with a low-density core.
Additional Information
© 2014 American Association for the Advancement of Science. 8 January 2014; accepted 24 February 2014. L.I., M.P., M.D., and P.T. acknowledge support from the Italian Space Agency. D.H., F.N., and J.I.L. are grateful to NASA for support through the Cassini Project. The work of R.A.J., J.W.A., and S.W.A. was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. The Doppler data and ancillary information used in this analysis are archived in NASA's Planetary Data System.Attached Files
Supplemental Material - Iess-SM.pdf
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Additional details
- Eprint ID
- 45462
- Resolver ID
- CaltechAUTHORS:20140502-093023240
- Agenzia Spaziale Italiana (ASI)
- NASA/JPL/Caltech
- Created
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2014-05-05Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences (GPS)