The effect of Jupiter oscillations on Juno gravity measurements

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• 作者：Daniele Durante ; ^a ; ^{daniele.durante@uniroma1.it" class="auth_mail" title="E-mail the corresponding author} ; Tristan Guillot^b ; ^{tristan.guillot@oca.eu" class="auth_mail" title="E-mail the corresponding author} ; Luciano Iess^a ; ^{luciano.iess@uniroma1.it" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Geophysics ; Jupiter interior ; Orbit determination
• 刊名：Icarus
• 出版年：2017
• 出版时间：15 January 2017
• 年：2017
• 卷：282
• 期：Complete
• 页码：174-182
• 全文大小：2176 K

文摘

Seismology represents a unique method to probe the interiors of giant planets. Recently, Saturn’s f-modes have been indirectly observed in its rings, and there is strong evidence for the detection of Jupiter global modes by means of ground-based, spatially-resolved, velocimetry measurements. We propose to exploit Juno’s extremely accurate radio science data by looking at the gravity perturbations that Jupiter’s acoustic modes would produce. We evaluate the perturbation to Jupiter’s gravitational field using the oscillation spectrum of a polytrope with index 1 and the corresponding radial eigenfunctions. We show that Juno will be most sensitive to the fundamental mode (n=0$n=0$), unless its amplitude is smaller than 0.5 cm/s, i.e. 100 times weaker than the $n\sim 4-11$ modes detected by spatially-resolved velocimetry. The oscillations yield contributions to Juno’s measured gravitational coefficients similar to or larger than those expected from shallow zonal winds (extending to depths less than 300 km). In the case of a strong f-mode (radial velocity ∼ 30 cm/s), these contributions would become of the same order as those expected from deep zonal winds (extending to 3000 km), especially on the low degree zonal harmonics, therefore requiring a new approach to the analysis of Juno data.