Mercury's moment of inertia from spin and gravity data

被引：92

作者：

Margot, Jean-Luc ^{[1
,2
]}

Peale, Stanton J. ^{[3
]}

Solomon, Sean C. ^{[4
,5
]}

Hauck, Steven A., II ^{[6
]}

Ghigo, Frank D. ^{[7
]}

Jurgens, Raymond F. ^{[8
]}

Yseboodt, Marie ^{[9
]}

Giorgini, Jon D. ^{[8
]}

Padovan, Sebastiano ^{[1
]}

Campbell, Donald B. ^{[10
]}

机构：

[1] Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA

[2] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA

[3] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA

[4] Carnegie Inst Sci, Dept Terr Magnetism, Washington, DC 20015 USA

[5] Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY USA

[6] Case Western Reserve Univ, Dept Earth Environm & Planetary Sci, Cleveland, OH 44106 USA

[7] Natl Radio Astron Lab, Green Bank, WV USA

[8] CALTECH, Jet Prop Lab, Pasadena, CA USA

[9] Royal Observ Belgium, Uccle, Belgium

[10] Cornell Univ, Dept Astron, Ithaca, NY 14853 USA

来源：

JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS | 2012年 / 117卷

关键词：

MOLTEN CORE; LIBRATION; LONGITUDE; BODY;

D O I：

10.1029/2012JE004161

中图分类号：

P3 [地球物理学]; P59 [地球化学];

学科分类号：

0708 ; 070902 ;

摘要：

Earth-based radar observations of the spin state of Mercury at 35 epochs between 2002 and 2012 reveal that its spin axis is tilted by (2.04 +/- 0.08) arc min with respect to the orbit normal. The direction of the tilt suggests that Mercury is in or near a Cassini state. Observed rotation rate variations clearly exhibit an 88-day libration pattern which is due to solar gravitational torques acting on the asymmetrically shaped planet. The amplitude of the forced libration, (38.5 +/- 1.6) arc sec, corresponds to a longitudinal displacement of similar to 450 m at the equator. Combining these measurements of the spin properties with second-degree gravitational harmonics (Smith et al., 2012) provides an estimate of the polar moment of inertia of Mercury C/MR2 = 0.346 +/- 0.014, where M and R are Mercury's mass and radius. The fraction of the moment that corresponds to the outer librating shell, which can be used to estimate the size of the core, is C-m/C = 0.431 +/- 0.025.

引用

页数：11

共 29 条

[1] Ancillary data services of NASA's Navigation and Ancillary Information Facility [J].

Acton, CH .

PLANETARY AND SPACE SCIENCE, 1996, 44 (01) :65-70

[2]

[Anonymous], 1971, Random Data: Analysis and Measurement Procedures

[3] The free librations of Mercury and the size of its inner core [J].

Dumberry, M. .

GEOPHYSICAL RESEARCH LETTERS, 2011, 38

[4]

Einstein A, 1905, ANN PHYS-BERLIN, V17, P891

[5] Predicted recovery of Mercury's internal structure by MESSENGER [J].

Hauck, Steven A., II ;

Solomon, Sean C. ;

Smith, Derek A. .

GEOPHYSICAL RESEARCH LETTERS, 2007, 34 (18)

[6]

Holin I. V., 1988, RADIOPHYS QUANT EL, V31, P515

[7]

Holin I. V., 1992, RADIOPHYS QUANT EL, V35, P433

[8] Mars high resolution gravity fields from MRO, Mars seasonal gravity, and other dynamical parameters [J].

Konopliv, Alex S. ;

Asmar, Sami W. ;

Folkner, William M. ;

Karatekin, Ozgur ;

Nunes, Daniel C. ;

Smrekar, Suzanne E. ;

Yoder, Charles F. ;

Zuber, Maria T. .

ICARUS, 2011, 211 (01) :401-428

[9] Large longitude libration of Mercury reveals a molten core [J].

Margot, J. L. ;

Peale, S. J. ;

Jurgens, R. F. ;

Slade, M. A. ;

Holin, I. V. .

SCIENCE, 2007, 316 (5825) :710-714

[10] A Mercury orientation model including non-zero obliquity and librations [J].

Margot, Jean-Luc .

CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY, 2009, 105 (04) :329-336

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