Juno spacecraft gravity measurements provide evidence for normal modes of Jupiter

The Juno spacecraft's gravity science experiment precisely measured Jupiter's zonal gravitational field. Analysis of 22 Juno gravity passes reveals new gravity field features with a time-variable component. The study shows that normal modes of the planet better explain these anomalous signatures than localized density anomalies or non-axisymmetric components of the static gravity field. The analysis identifies p-modes with a peak radial velocity of 10–50 cm/s at 900–1200 μHz and provides upper bounds on lower frequency f-modes. These findings open possibilities for exploring gas giant interiors via time-variable gravity measurements or onboard instrumentation devoted to normal mode observation.

Daniele Durante, Tristan Guillot, Luciano Iess, David J. Stevenson, Christopher R. Mankovich, Steve Markham, Eli Galanti, Yohai Kaspi, Marco Zannoni, Luis Gomez Casajus, Giacomo Lari, Marzia Parisi, Dustin R. Buccino, Ryan S. Park, Scott J. Bolton