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The tides of Titan
Luciano Iess1, Robert A Jacobson, Marco Ducci
1Dipartimento di Ingegneria Meccanica e Aerospaziale, Università La Sapienza, via Eudossiana 18, 00184 Rome, Italy. luciano.iess@uniroma1.it
Science (New York, N.Y.)
|June 30, 2012
Summary
Cassini spacecraft data reveals Titan experiences periodic tidal stresses from Saturn
Area of Science:
- Planetary Science
- Astrogeology
- Orbital Dynamics
Background:
- Titan orbits Saturn in a 16-day period with an orbital eccentricity of 0.028.
- Tidal forces are known to influence planetary bodies, causing deformation and internal stresses.
Purpose of the Study:
- To detect and quantify the signature of periodic tidal stresses within Saturn's moon Titan.
- To investigate Titan's internal structure and composition based on its response to tidal forces.
Main Methods:
- Analysis of precise acceleration measurements of the Cassini spacecraft during six close flybys (2006-2011).
- Determination of Titan's degree-2 Love number (k(2)) from gravity field variations.
Main Results:
- Detected periodic changes in Titan's quadrupole gravity, approximately 4% of the static value.
- Calculated two independent values for the degree-2 Love number: k(2) = 0.589 ± 0.150 and k(2) = 0.637 ± 0.224 (2σ).
Conclusions:
- Titan's interior must be deformable on orbital timescales to account for the observed tidal response.
- The findings strongly suggest the presence of a global subsurface ocean within Titan.
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