The Permanent and Inductive Magnetic Moments of Ganymede

Kivelson, M. G.; Khurana, K. K.; Volwerk, M.

doi:10.1006/icar.2002.6834

Cited by 362 publications

(481 citation statements)

References 27 publications

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“…All models are composed of an ice shell including a subsurface ocean and a rocky mantle. Oceans are predicted for all three satellites (Kivelson et al 1999(Kivelson et al , 2000(Kivelson et al , 2002Khurana 1998;Papalardo et al 1999) and theoretical models shows that internal oceans are conceivable for Europa, Ganymede and for a partly differentiated Callisto with thicknesses as large as few hundred km (Schubert et al 2004). The Europa ocean is likely situated above the rocky mantle.…”

Section: Interior Modelsmentioning

confidence: 99%

“…The presence of an ocean for the Galilean satellites is inferred from analysis of the geological structures at the surface of the satellites and magnetic measurements (Kivelson et al 1999(Kivelson et al , 2000(Kivelson et al , 2002Khurana 1998;Papalardo et al 1999). Van Hoolst et al (2008, 2009) and Baland & Van Hoolst (2010) have investigated the librational response of the Galilean satellites and Titan in the presence of a subsurface ocean and showed that it increases the librational amplitude.…”

Section: Introductionmentioning

confidence: 99%

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Librational response of Europa, Ganymede, and Callisto with an ocean for a non-Keplerian orbit

Rambaux

Hoolst

Karatekin

2011

A&A

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Context. The Galilean satellites Europa, Ganymede, and Callisto are thought to harbor a subsurface ocean beneath an ice shell but its properties, such as the depth beneath the surface, have not been well constrained. Future geodetic observations with, for example, space missions like the Europa Jupiter System Mission (EJSM) of NASA and ESA may refine our knowledge about the shell and ocean. Aims. Measurement of librational motion is a useful tool for detecting an ocean and characterizing the interior parameters of the moons. The objective of this paper is to investigate the librational response of Galilean satellites, Europa, Ganymede, and Callisto assumed to have a subsurface ocean by taking the perturbations of the Keplerian orbit into account. Perturbations from a purely Keplerian orbit are caused by gravitational attraction of the other Galilean satellites, the Sun, and the oblateness of Jupiter. Methods. We use the librational equations developed for a satellite with a subsurface ocean in synchronous spin-orbit resonance. The orbital perturbations were obtained from recent ephemerides of the Galilean satellites. Results. We identify the wide frequency spectrum in the librational response for each Galilean moon. The librations can be separated into two groups, one with short periods close to the orbital period, and a second group of long-period librations related to the gravitational interactions with the other moons and the Sun. Long-period librations can have amplitudes as large as or even larger than the amplitude of the main libration at orbital period for the Keplerian problem, implying the need to introduce them in analyses of observations linked to the rotation. The amplitude of the short-period librations contains information on the interior of the moons, but the amplitude associated with long periods is almost independent of the interior at first order in the low frequency. For Europa, we identified a short-period libration with period close to twice the orbital period, which could have been resonantly amplified in the history of Europa. For Ganymede, we also found a possible resonance between a proper period and a forced period when the icy shell thickness is around 50 km. The librations of Callisto are dominated by solar perturbations.

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Section: Interior Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Librational response of Europa, Ganymede, and Callisto with an ocean for a non-Keplerian orbit

Rambaux

Hoolst

Karatekin

2011

A&A

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“…Galileo magnetic field measurements have found indications of subsurface oceans on Europa (Khurana et al 1998;Kivelson et al 1999), Ganymede (Kivelson et al 2002) and Callisto (Khurana et al 1998;Kivelson et al 1999) where endogenic chemistry is likely to have influenced the composition of these internal oceans. The extensive resurfacing of Europa and Ganymede suggest exchange between an interior ocean and the surface.…”

Section: The Galilean Satellitesmentioning

confidence: 99%

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

et al. 2015

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Comets play a dual role in understanding the formation and evolution of the solar system. First, the composition of comets provides information about the origin of the giant planets and their moons because comets formed early and their composition is not expected to have evolved significantly since formation. They, therefore serve as a record of conditions during the early stages of solar system formation. Once comets had formed, their orbits were perturbed allowing them to travel into the inner solar system and impact the planets. In this way they contributed to the volatile inventory of planetary atmospheres. We review here how knowledge of comet composition up to the time of the Rosetta mission has contributed to understanding the formation processes of the giant planets, their moons and small icy bodies in the solar system. We also discuss how comets contributed to the volatile inventories of the giant and terrestrial planets.

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“…Some satellites even possess their own magnetic field which interacts with the parent's one [e.g., Europa has an induced magnetic field (Kivelson et al 2000), Ganymede has an intrinsic magnetic field (Kivelson et al 2002)]. …”

Section: Magnetospherementioning

confidence: 99%

What characterizes planetary space weather?

Lilensten

Coates

Déhant

et al. 2014

Astron Astrophys Rev

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Space weather has become a mature discipline for the Earth space environment. With increasing efforts in space exploration, it is becoming more and more necessary to understand the space environments of bodies other than Earth. This is the background for an emerging aspect of the space weather discipline: planetary space weather. In this article, we explore what characterizes planetary space weather, using some examples throughout the solar system. We consider energy sources and timescales, the characteristics of solar system objects and interaction processes. We

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The Permanent and Inductive Magnetic Moments of Ganymede

Abstract: Data acquiredby the Galileo magnetometer on five passes by Ganymede have been used to characterize Ganymede's internal magnetic moments.

Cited by 362 publications

References 27 publications

Librational response of Europa, Ganymede, and Callisto with an ocean for a non-Keplerian orbit

Librational response of Europa, Ganymede, and Callisto with an ocean for a non-Keplerian orbit

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

What characterizes planetary space weather?

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