Large longitude libration of Mercury reveals a molten core.
نویسندگان
چکیده
Observations of radar speckle patterns tied to the rotation of Mercury establish that the planet occupies a Cassini state with obliquity of 2.11 +/- 0.1 arc minutes. The measurements show that the planet exhibits librations in longitude that are forced at the 88-day orbital period, as predicted by theory. The large amplitude of the oscillations, 35.8 +/- 2 arc seconds, together with the Mariner 10 determination of the gravitational harmonic coefficient C22, indicates that the mantle of Mercury is decoupled from a core that is at least partially molten.
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ورودعنوان ژورنال:
- Science
دوره 316 5825 شماره
صفحات -
تاریخ انتشار 2007