We have detected in Cassini spacecraft data the signature of the periodic tidal stresses within Titan, driven by the eccentricity (e = 0.028) of its 16-day orbit around Saturn. Precise measurements of the acceleration of Cassini during six close flybys between 2006 and 2011 have revealed that Titan responds to the variable tidal field exerted by Saturn with periodic changes of its quadrupole gravity, at about 4% of the static value. Two independent determinations of the corresponding degree-2 Love number yield k2 = 0.589 +/- 0.150 and k2 = 0.637 +/- 0.224 (2sigma). Such a large response to the tidal field requires that Titan’s interior be deformable over time scales of the orbital period, in a way that is consistent with a global ocean at depth.
The Tides of Titan / L. Iess; R.A. Jacobson; M. Ducci; D.J. Stevenson; J.I. Lunine; J.W. Armstrong; S.W. Asmar; P. Racioppa; N.J. Rappaport; P. Tortora. - In: SCIENCE. - ISSN 0036-8075. - STAMPA. - 337:(2012), pp. 457-459. [10.1126/science.1219631]
The Tides of Titan
TORTORA, PAOLO
2012
Abstract
We have detected in Cassini spacecraft data the signature of the periodic tidal stresses within Titan, driven by the eccentricity (e = 0.028) of its 16-day orbit around Saturn. Precise measurements of the acceleration of Cassini during six close flybys between 2006 and 2011 have revealed that Titan responds to the variable tidal field exerted by Saturn with periodic changes of its quadrupole gravity, at about 4% of the static value. Two independent determinations of the corresponding degree-2 Love number yield k2 = 0.589 +/- 0.150 and k2 = 0.637 +/- 0.224 (2sigma). Such a large response to the tidal field requires that Titan’s interior be deformable over time scales of the orbital period, in a way that is consistent with a global ocean at depth.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
