Large Longitude Libration of Mercury Reveals a Molten Core

@article{Margot2007LargeLL,
  title={Large Longitude Libration of Mercury Reveals a Molten Core},
  author={Jean-Luc Margot and Stanton J. Peale and Raymond F. Jurgens and Martin A. Slade and Igor V. Holin},
  journal={Science},
  year={2007},
  volume={316},
  pages={710 - 714}
}
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… 

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References

SHOWING 1-10 OF 43 REFERENCES

Rotational Period of the Planet Mercury

IN a recent communication by S. J. Peale and T. Gold1 the rotational period of Mercury, determined from radar Doppler-spread measurements to be 59 ± 5 days2, has been explained in terms of a solar

Rotation of the Planet Mercury

SOLAR tidal friction must be an intense effect for Mercury, and it must be expected that the planet's spin would have relaxed from any original value to one that is under the control of this effect

A procedure for determining the nature of Mercury's core

Abstract— We review the assertion that the precise measurement of the second degree gravitational harmonic coefficients, the obliquity, and the amplitude of the physical libration in longitude, C20,

The magnetic field of Mercury, 1

An updated analysis and interpretation are presented of the magnetic field observations obtained during the Mariner 10 encounter with the planet Mercury on March 29, 1974. The combination of data

Does Mercury have a molten core?

THE discovery of an intrinsic magnetic field for the planet Mercury by Mariner 10 (ref. 1) and its preferred source in an internal dynamo2 imply the existence of a conducting molten core. We propose

Radar mapping of Mercury's polar anomalies

GROUND-based radar observations of Mercury have revealed unusually strong, highly depolarized echoes from the north1,2 and south2 poles. These anomalous echoes have been cited as evidence of polar