Large longitude libration of Mercury reveals a molten core

被引:244
作者
Margot, J. L.
Peale, S. J.
Jurgens, R. F.
Slade, M. A.
Holin, I. V.
机构
[1] Cornell Univ, Dept Astron, Ithaca, NY 14853 USA
[2] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
[3] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA
[4] Space Res Inst, Moscow, Russia
关键词
D O I
10.1126/science.1140514
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
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 C-22, indicates that the mantle of Mercury is decoupled from a core that is at least partially molten.
引用
收藏
页码:710 / 714
页数:5
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