The moment of inertia and isostasy of Mars

Reasenberg, R. D.

doi:10.1029/jb082i002p00369

Cited by 94 publications

(44 citation statements)

References 10 publications

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“…The range of I * in (1) is used as a constraint for trial models of the internal structure of Mars. This result is close to the value of this ratio that was predicted by Reasenberg (1977) and Kaula (1979) long before the Mars Pathfinder mission.…”

Section: Introductionsupporting

confidence: 87%

Construction of Martian Interior Model

Жарков

Гудкова

2005

Sol Syst Res

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In most of these papers, the authors constructed models of the Martian interior using a chemical model suggested by W ä nke and Dreibus (the DW model; see W ä nke, 1981 ; Dreibus and W ä nke, 1989; W ä nke and Dreibus, 1994). Abstract -We present the results of extensive numerical modeling of the Martian interior. Yoder et al. in 2003 reported a mean moment of inertia of Mars that was somewhat smaller than the previously used value and the Love number k 2 obtained from observations of solar tides on Mars. These values of k 2 and the mean moment of inertia impose a strong new constraint on the model of the planet. The models of the Martian interior are elastic, while k 2 contains both elastic and inelastic components. We thoroughly examined the problem of partitioning the Love number k 2 into elastic and inelastic components. The information necessary to construct models of the planet (observation data, choice of a chemical model, and the cosmogonic aspect of the problem) are discussed in the introduction. The model of the planet comprises four submodels-a model of the outer porous layer, a model of the consolidated crust, a model of the silicate mantle, and a core model. We estimated the possible content of hydrogen in the core of Mars. The following parameters were varied while constructing the models: the ferric number of the mantle (Fe#) and the sulfur and hydrogen content in the core. We used experimental data concerning the pressure and temperature dependence of elastic properties of minerals and the information about the behavior of Fe ( γ -Fe ), FeS, FeH, and their mixtures at high P and T . The model density, pressure, temperature, and compressional and shear velocities are given as functions of the planetary radius. The trial model M13 has the following parameters: Fe# = 0.20; 14 wt % of sulfur in the core; 50 mol % of hydrogen in the core; the core mass is 20.9 wt %; the core radius is 1699 km; the pressure at the mantle-core boundary is 20.4 GPa; the crust thickness is 50 km; Fe is 25.6 wt %; the Fe/Si weight ratio is 1.58, and there is no perovskite layer. The model gives a radius of the Martian core within 1600-1820 km while ≥ 30 mol % of hydrogen is incorporated into the core. When the inelasticity of the Martian interior is taken into account, the Love number k 2 increases by several thousandths; therefore, the model radius of the planetary core increases as well. The prognostic value of the Chandler period of Mars is 199.5 days, including one day due to inelasticity. Finally, we calculated parameters of the equilibrium figure of Mars for the M13 model: = 1.82 × 10 -3 , = -7.79 × 10 -6 , = 1/242.3 (the dynamical flattening of the core-mantle boundary). J 2 0 J 4 0 e c-m D 344 SOLAR SYSTEM RESEARCH Vol. 39 No. 5 2005 ZHARKOV, GUDKOVA

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Section: Introductionsupporting

confidence: 87%

Construction of Martian Interior Model

Жарков

Гудкова

2005

Sol Syst Res

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“…The Viking estimate for the precession constrains the pole moment to 0.357 + 0.016. This provocative estimate lies between the upper bound 0.365 deduced by Reasenberg [1977] and Kaula et al [1989] from the assumption that the nonhydrostatic component of the observed J2 is a prolate spheroid centered on Tharsis and the value of 0.345 derived by Bills [1989] based on an alternative partitioning of the observed oblateness into hydrostatic and nonhydrostatic components.…”

Section: Introductionmentioning

confidence: 98%

Mars dynamics from Earth‐based tracking of the Mars Pathfinder lander

Folkner¹,

Kahn²,

Preston³

et al. 1997

J. Geophys. Res.

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Abstract.Measurements of Mars' rotational variations can be conducted via Earth-based radio tracking observations of the Mars Pathfinder lander during an extended mission. Two-way range measurements between an Earth tracking station and the lander will enable precise monitoring of the planet's orientation, allowing details of Mars' internal structure and global surface/atmosphere interactions to be determined. An analysis has been performed to investigate the accuracy with which key physical parameters of Mars can be determined using the Earth-based radio tracking measurements. Acquisition of such measurements over one Martian year should enable determination of Mars' polar moment of inertia to 1% or better, providing a strong constraint on radial density profiles (and hence on the iron content of the core and mantle) and on long-term variations of the obliquity, which influences the climate. Variations in Mars length of day and polar motion should also be detectable, and will yield information on the seasonal cycling of carbon dioxide between the atmosphere and the surface.

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“…Revision of the latter from C/MR 2 =o.377+_o.ool to o.365 + o.ooI (Reasenberg, 1977) resulted in major transfer of mass towards the planetary centre, but the history of the lunar moment-of-inertia does not inspire confidence in the latest Martian value. Cosmochemical models for the planets are also highly uncertain, and present data on the volatiles on Mars are perhaps more easily interpreted in terms of a volatile-poor than a volatile-rich planet ( Anders and Owen,I977).…”

Section: Geophysical and Geochemical Modelsmentioning

confidence: 99%

Mineralogy of the planets: a voyage in space and time

Smith

1979

Mineral. mag.

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Equilibrium progressive condensation of the solar nebula is regarded as a useful theoretical boundary, but complex processes involving crystal-liquid differentiation in, and collisions between, planetesimals are used to interpret the properties of meteorites and terrestrial planets. Chemical differentiation in the nebula begins with condensation and aggregation of dust, which can yield oxidized and reduced products depending whether C/O is less or greater than unity. Simple models for direct accretion of condensed materials into planets are reviewed but not adopted. For the Earth, the early history is constrained by Archaean rocks dating from -3.8 x lO 9 yr whose properties indicate a non-reducing atmosphere, and a mantle that yielded volcanic rocks mostly similar to recent ones. Physical interactions involving small bodiesThe upper mantle (above 200 km depth) contains peridotitic rocks attributable to crystal-liquid differentiation and metamorphism. Volatile elements exist in mica and other minerals, but are sparse. Abundances of sider0Phile and chalcophile elements are high enough to require late accretion of material rich in these elements, the presence of a barrier between upper mantle and core, and some extraction by sinking sulphide. The mantle (deeper than 200 kin) and core are inaccessible to direct study but interpretation of seismic data coupled with high-pressure laboratory studies requires inversion to dense phases in the mantle (especially perovskite?) and presence of light elements in the core (mainly S?). The bulk composition is modelled by cosmochemical analogy constrained by geophysical and geochemical parameters. The early condensate may be augmented by 1. 5 +0.5? over (Mg+Si), and metal by 1.2++O.I?, while alkalies are probably depleted six-fold. Radial heterogeneity from a reduced interior to an oxidized exterior is suggested. For the Moon, sections cover observations, petrologic interpretations, and bulk chemical composition. For the origin of the

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The moment of inertia and isostasy of Mars

Cited by 94 publications

References 10 publications

Construction of Martian Interior Model

Construction of Martian Interior Model

Mars dynamics from Earth‐based tracking of the Mars Pathfinder lander

Mineralogy of the planets: a voyage in space and time

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