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Updated spherical harmonic moments of Ganymede from the Juno flyby
  • +3
  • Tristan Weber,
  • Kimberly M Moore,
  • John E. P. Connerney,
  • Jared Randolph Espley,
  • Gina A. DiBraccio,
  • Norberto Romanelli
Tristan Weber
NASA Goddard Space Flight Center

Corresponding Author:tristan.weber@colorado.edu

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Kimberly M Moore
California Institute of Technology
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John E. P. Connerney
NASA Goddard Space Flight Center
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Jared Randolph Espley
NASA Goddard
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Gina A. DiBraccio
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Norberto Romanelli
NASA Goddard Space Flight Center
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In this study, we use data from the Juno and Galileo spacecraft to analyze the internal magnetic dynamo of Ganymede. As the only known moon with a strong internal magnetic field, Ganymede is a uniquely interesting object in the context of understanding the formation and structure of planetary magnetospheres. Using a spherical harmonic model centered on the moon, we report a dipole approximation for Ganymede of g01 = -716.4 nT, g11 = 56.0 nT, and h11 = 27.0 nT. We find that using a quadrupole fit rather than a dipole fit provides only a marginal increase in accuracy, and instead favor the use of a dipole approximation until more data can be obtained. The magnetic moment estimates provided here can be used as a baseline for interpreting data from future spacecraft flybys of the moon, and can serve as inputs into numerical models studying Ganymede’s magnetosphere.