High-order gravity field models for Jupiter in support of NASA's Juno mission

• Applicant: Dr. Nadine Nettelmann
• Subject Area: Astrophysics and Astronomy ; Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 278011549

Planetary climate, origin, and conditions for life are subjects of general interest to the public. Understanding how an entire planet other than Earth works, in particular the coupling between the atmosphere, interior, and environment, can yield insight into the nature of the world we live in. In this regard, the gas giant planet Jupiter --albeit itself hostile to life-- offers unique possibilities. Jupiter's atmospheric winds, gravity field, and water abundance will be measured to unprecedented high accuracy by spacecraft Juno launched in 2011. However, the information of interest contained in those data is only indirectly accessible. To extract, for instance, the depth of zonal flows and the core mass, models for Jupiter's gravity field, interior, and atmosphere are required; in particular, significantly more accurate models than currently exist.The objective of this proposal is to develop new Jupiter models that(1) allow to provide the high-order gravity field contributions which are necessary for deriving the wind contribution, as together they probe the interaction between atmosphere and interior, and (2) to account for He sedimentation in a parameterized and physically self-consistent manner so that the improved models can be compared against the water abundance to be observed by Juno. Those models will yield new constraints on Jupiter's core mass, heavy elements content, and advance our understanding of the physics of H/He mixtures under high pressures. The gravity field will be computed up to 7th order using two alternative methods: the recently developed method of Concentric Maclaurin Spheroids, and an expansion, to be developed as part of this work, of the commonly used Theory of Figures. Underlying parameterized Jupiter evolution models will be based on ab inito data for the equations of state and for the H/He phase diagram. In particular, the standard assumption of a convectively unstable planet interior, as is the case for Earth, will be investigated in the presence of a compositional gradient. Optional projects are designed for potential student participation.

• DFG Programme: Research Grants