Gravitational constraints on the internal structure of Ganymede
Article Abstract:
The measurement of Ganymede's overall density and the spherical harmonics, J2 and C22, of its gravitational field by Galileo spacecraft reveals the presence of a core and mantle. These results in conjunction with the presence of an internal magnetic field in Ganymede suggest that a silicate mantle surrounds the metallic core of radius 400-1300 km. An 800 km thick ice shell surrounds the mantle. The core accounts for one-third of the total mass. Ganymede without the ice layer, resembles Io in terms of size and internal mass distribution.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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Discovery of Ganymede's magnetic field by the Galileo spacecraft
Article Abstract:
The encounter of Galileo spacecraft with Ganymede, Jupiter's largest moon reveals the the presence of an internal magnetic field. The data agrees with the observation of an equatorial surface field strength of 750 nT and a 10 degree tilt of Ganymede-centered magnetic dipole with respect to the spin axis. The magnetic field is strong enough to produce a magnetosphere with well-defined boundaries in Ganymede. The observations fail to indicate the source of the internal magnetic field.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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Absence of an internal magnetic field at Callisto
Article Abstract:
The findings provided by the Galileo spacecraft during its fly-by of Callisto reveals the absence of an internally generated magnetic field in the said galilean moon. Magnetometer observations from the said fly-by reveal that changes in the plasma environment may have minimized field strength. These observations are different from the results taken from the Ganymede and Io moons.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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