Gravity Field and Internal Structure of Mercury from MESSENGER

• Published in: Science (American Association for the Advancement of Science) Vol. 336; no. 6078; pp. 214 - 217
• Main Authors: Smith, David E., Zuber, Maria T., Phillips, Roger J., Solomon, Sean C., Hauck, Steven A., Lemoine, Frank G., Mazarico, Erwan, Neumann, Gregory A., Peale, Stanton J., Margot, Jean-Luc, Johnson, Catherine L., Torrence, Mark H., Perry, Mark E., Rowlands, David D., Goossens, Sander, Head, James W., Taylor, Anthony H.
• Format: Journal Article
• Language: English
• Published: 2230 Support American Association for the Advancement of Science 13.04.2012; The American Association for the Advancement of Science
• Subjects: Astronomy; Crusts; Density distribution; Earth, ocean, space; Exact sciences and technology; Geoids; Gravitational anomalies; Gravitational fields; Gravity anomalies; Liquids; Lunar and Planetary Science and Exploration; Mantle; Mass; Mass, size; gravitational fields; rotation; orbits; Mercury; Moments of inertia; Northern Hemisphere; Planetary, asteroid, and satellite characteristics and properties; Planets, their satellites and rings. Asteroids; Scientific Concepts; Silicates; Solar system; Solids; Thinning; Radial distribution; Northern hemisphere; Mercury planet; Internal structure; Anomaly; Models; Density distribution; Moment of inertia; Gravity; Messenger space probe
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1218809

Radio tracking of the MESSENGER spacecraft has provided a model of Mercury's gravity field. In the northern hemisphere, several large gravity anomalies, including candidate mass concentrations (mascons), exceed 100 mi Hi-Galileos (mgal). Mercury's northern hemisphere crust is thicker at low latitudes and thinner in the polar region and shows evidence for thinning beneath some impact basins. The low-degree gravity field, combined with planetary spin parameters, yields the moment of inertia CIMR² = 0.353 ± 0.017, where M and R are Mercury's mass and radius, and a ratio of the moment of inertia of Mercury's solid outer shell to that of the planet of CJC = 0.452 ± 0.035. A model for Mercury's radial density distribution consistent with these results includes a solid silicate crust and mantle overlying a solid iron-sulfide layer and an iron-rich liquid outer core and perhaps a solid inner core.