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The Gravity Field and Interior Structure of Enceladus

Iess, L. and Stevenson, D. J. and Parisi, M. and Hemingway, D. and Jacobson, R. A. and Lunine, J. I. and Nimmo, F. and Armstrong, J. W. and Asmar, S. W. and Ducci, M. and Tortora, P. (2014) The Gravity Field and Interior Structure of Enceladus. Science, 344 (6179). pp. 78-80. ISSN 0036-8075. http://resolver.caltech.edu/CaltechAUTHORS:20140502-093023240

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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.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1126/science.1250551 DOIArticle
http://www.sciencemag.org/content/344/6179/78PublisherArticle
ORCID:
AuthorORCID
Stevenson, D. J.0000-0001-9432-7159
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.
Funders:
Funding AgencyGrant Number
Agenzia Spaziale Italiana (ASI)UNSPECIFIED
NASA/JPL/CaltechUNSPECIFIED
Record Number:CaltechAUTHORS:20140502-093023240
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140502-093023240
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:45462
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:05 May 2014 17:14
Last Modified:24 Nov 2015 00:35

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