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
Acton, CH
[J]. 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
Dumberry, M.
[J]. GEOPHYSICAL RESEARCH LETTERS, 2011, 38
[4] Einstein A, 1905, ANN PHYS-BERLIN, V17, P891
[5] Predicted recovery of Mercury's internal structure by MESSENGER
Hauck, Steven A., II
Solomon, Sean C.
Smith, Derek A.
[J]. 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
Konopliv, Alex S.
Asmar, Sami W.
Folkner, William M.
Karatekin, Ozgur
Nunes, Daniel C.
Smrekar, Suzanne E.
Yoder, Charles F.
Zuber, Maria T.
[J]. ICARUS, 2011, 211 (01) : 401 - 428
[9] Large longitude libration of Mercury reveals a molten core
Margot, J. L.
Peale, S. J.
Jurgens, R. F.
Slade, M. A.
Holin, I. V.
[J]. SCIENCE, 2007, 316 (5825) : 710 - 714
[10] A Mercury orientation model including non-zero obliquity and librations
Margot, Jean-Luc
[J]. CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY, 2009, 105 (04) : 329 - 336

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