RT Journal Article
SR Electronic
T1 Size and Shape of Saturn's Moon Titan
JF Science
JO Science
FD American Association for the Advancement of Science
SP 921
OP 923
DO 10.1126/science.1168905
VO 324
IS 5929
A1 Zebker, Howard A.
A1 Stiles, Bryan
A1 Hensley, Scott
A1 Lorenz, Ralph
A1 Kirk, Randolph L.
A1 Lunine, Jonathan
YR 2009
UL http://science.sciencemag.org/content/324/5929/921.abstract
AB Cassini observations show that Saturn’s moon Titan is slightly oblate. A fourth-order spherical harmonic expansion yields north polar, south polar, and mean equatorial radii of 2574.32 ± 0.05 kilometers (km), 2574.36 ± 0.03 km, and 2574.91 ± 0.11 km, respectively; its mean radius is 2574.73 ± 0.09 km. Titan’s shape approximates a hydrostatic, synchronously rotating triaxial ellipsoid but is best fit by such a body orbiting closer to Saturn than Titan presently does. Titan’s lack of high relief implies that most—but not all—of the surface features observed with the Cassini imaging subsystem and synthetic aperture radar are uncorrelated with topography and elevation. Titan’s depressed polar radii suggest that a constant geopotential hydrocarbon table could explain the confinement of the hydrocarbon lakes to high latitudes.