Obliquity tides do not significantly heat Enceladus

• Published in: Icarus (New York, N.Y. 1962) Vol. 214; no. 2; pp. 779 - 781
• Main Authors: Chen, E.M.A., Nimmo, F.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.08.2011; Elsevier
• Subjects: Astronomy; Cassini mission; Coefficients; Dissipation; Earth, ocean, space; Enceladus; Exact sciences and technology; Gravitation; Kinetic energy; Oceans; Rotational dynamics; Saturn, Satellites; Solar system; Tides; Saturn, Satellites; Rotational dynamics; Enceladus; Saturn planet; Satellites; Saturn; Dynamics; Saturn satellite; Solar system; Kinetic energy; Obliqueness; Heat transfer; Gravity
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1016/j.icarus.2011.06.007

Recently, Tyler [Tyler, R.H., 2009. Geophys. Res. Lett. 36, L15205; Tyler, R., 2011. Icarus, 211, 770–779] proposed that the tide due to an obliquity of greater than 0.1° might drive resonant flow in a liquid ocean at Enceladus, and that dissipation of the ocean’s kinetic energy may be an alternate source for the observed global heat flux. While there is currently no measurement of Enceladus’ obliquity, dissipation is expected to drive the spin pole to a Cassini state. Under this assumption, we find that Enceladus should occupy Cassini state 1 and that the obliquity of Enceladus should be less than 0.0015° for values of the degree-2 gravity coefficient C 2,2 between 1.0 × 10 −3 and 2.5 × 10 −3. Unless there is a significant free obliquity or the gravity coefficient C 2,2 has been significantly overestimated, it is unlikely that obliquity-driven flow in a subsurface ocean is the source of the extreme heat on Enceladus.