On 26th November 2005 Cassini spacecraft encountered Saturn satellite Rhea. Several analyses of radiometric data obtained during this flyby have been published. Their aim was to obtain the best estimate of the mass and the quadrupole gravity filed of Rhea. Here we present a new analysis to evaluate the effects of the gravity anomaly produced by Tirawa impact basin on the gravity field estimate. Moreover we evaluated the amount of the reorientation of the inertia ellipsoid caused by the mass redistribution occurred after the impact. Results show that the estimate is strongly influenced by Tirawa basin. The quadrupole gravity field is affected and the solution moves towards the hydrostatic equilibrium even if it is not reached. Furthermore the reorientation of the inertia ellipsoid is of about 1°-2°. © SAIt 2012.
The effect of Tirawa impact basin on the determination of Rhea's gravity field / Ducci, M; Iess, Luciano; Giese, B.; Mackenzie, R.. - In: MEMORIE DELLA SOCIETÀ ASTRONOMICA ITALIANA. - ISSN 1824-016X. - STAMPA. - 20:(2012), pp. 132-134. (Intervento presentato al convegno 10th Italian National Conference on Planetary Science tenutosi a ita nel 2011).
The effect of Tirawa impact basin on the determination of Rhea's gravity field
IESS, Luciano;
2012
Abstract
On 26th November 2005 Cassini spacecraft encountered Saturn satellite Rhea. Several analyses of radiometric data obtained during this flyby have been published. Their aim was to obtain the best estimate of the mass and the quadrupole gravity filed of Rhea. Here we present a new analysis to evaluate the effects of the gravity anomaly produced by Tirawa impact basin on the gravity field estimate. Moreover we evaluated the amount of the reorientation of the inertia ellipsoid caused by the mass redistribution occurred after the impact. Results show that the estimate is strongly influenced by Tirawa basin. The quadrupole gravity field is affected and the solution moves towards the hydrostatic equilibrium even if it is not reached. Furthermore the reorientation of the inertia ellipsoid is of about 1°-2°. © SAIt 2012.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
