A model of Saturn inferred from its measured gravitational field. (April 2018)

• Record Type: Journal Article
• Authors: Kong, Dali; Zhang, Keke; Schubert, Gerald; Anderson, John D.
• Is Part Of: Research in astronomy and astrophysics. Volume 18:Number 4(2018:Apr.)
• Publication Date: 2018-04
• Subjects: gravitation -- planets and satellites: individual (Saturn) -- planets and satellites: interiors; Astronomy -- Periodicals; Astrophysics -- Periodicals; 520.5
• DOI: 10.1088/1674-4527/18/4/38
• Languages: English
• ISSNs: 1674-4527

Abstract

Abstract: We present an interior model of Saturn with an ice-rock core, a metallic region, an outer molecular envelope and a thin transition layer between the metallic and molecular regions. The shape of Saturn's 1 bar surface is irregular and determined fully self-consistently by the required equilibrium condition. While the ice-rock core is assumed to have a uniform density, three different equations of state are adopted for the metallic, molecular and transition regions. The Saturnian model is constrained by its known mass, its known equatorial and polar radii, and its known zonal gravitational coefficients, J 2 n, n = 1, 2, 3. The model produces an ice-rock core with equatorial radius 0.203 R S, where R S is the equatorial radius of Saturn at the 1-bar pressure surface; the core density ρ c = 10388.1 kgm −3 corresponding to 13.06 Earth masses; and an analytical expression describing the Saturnian irregular shape of the 1-bar pressure level. The model also predicts the values of the higher-order gravitational coefficients, J 8, J 10 and J 12, for the hydrostatic Saturn and suggests that Saturn's convective dynamo operates in the metallic region approximately defined by 0.2 R S < r e < 0.7 R S, where r e denotes the equatorial radial distance from the Saturnian center of figure.