We propose a set of planetary interior models in agreement with the present knowledge of the plan... more We propose a set of planetary interior models in agreement with the present knowledge of the planet Mars. Our spherical, hydrostatic and non-rotating planet is constituted by a crust, parameterized by its mean density, a mantle with variable mineralogy, dependent on pressure and temperature and a partially fluid core composed of iron and sulfur. The crust thickness, the location of the core mantle boundary, the size and state of the inner-core and the concentration of sulfur in the core are adjusted to agree with the total mass and mean moment of inertia.
Despite the tight constraints put by seismology on the elastic properties of the Earth&am... more Despite the tight constraints put by seismology on the elastic properties of the Earth's lower mantle, its mineralogical composition and thermal state remain poorly known because the interpretation of seismic measurements suffers from the trade-off between temperature, iron content, and mineralogical composition. In order to overcome this difficulty, we complement seismic data with electromagnetic induction data. The latter data are
ABSTRACT Among all the planets of the solar system Mercury stands out, because it has a relativel... more ABSTRACT Among all the planets of the solar system Mercury stands out, because it has a relatively high average density compared to its size. To account for this high density, Mercury's core radius is thought to be larger than 34 of its radius. Here, we use recent data about the second-degree gravity field coefficients and measurements about Mercury's rotation – obliquity and 88-day libration amplitude – to obtain constraints on Mercury's interior structure. By combining the gravity field data and the obliquity measurements, the mean moment of inertia of Mercury can be determined. If the coupling between the core and the mantle is neglected then the gravity field data together with the libration amplitude provide an estimate of Mercury's silicate shell moment of inertia. However, since the effect of core–mantle coupling on the 88-day libration amplitude can be about as large as the libration amplitude's uncertainty (Van Hoolst et al., 2012) we use as data the mean moment of inertia and the 88-day libration amplitude to infer knowledge about Mercury's interior structure.
Mars' core is believed to be presently completely liquid. Though the presence of an inner co... more Mars' core is believed to be presently completely liquid. Though the presence of an inner core is not excluded. The existence of an inner core would induce a wobble of the planet which, if excited, could be seen in polar motion, i.e. in the motion of the instantaneous rotation axis in a frame tied to the planet. In this paper, we examine the consequences of an atmospheric excitation of that mode and of the classical Chandler wobble. The presence of an inner core induces also a free inner core nutation and consequently a resonance in the nutations of the planet. These nutations will be observed by the future experiment NEIGE (NEtlander Ionosphere and Geodesy Experiment). We will therefore compute the potential effect of an inner core on these observations.
ABSTRACT A new method is developed to determine the structure of telluric planetary interiors. It... more ABSTRACT A new method is developed to determine the structure of telluric planetary interiors. It is based on the joint inversion of data from in situÿgeophysical experiments and laboratory measurements. We infer conditional probability densities of the parameters governingÿthe internal structure by stochastic inversion. This multi-parameters approach is quite generic and canÿbe applied to any telluric planet. We illustrate it here withÿsimulated data of the future Netlanderÿmission to Mars. The simulated data come from the electromagnetic, geodetic and seismological experiments. This approach is free of any a priori assumption regarding theÿtemperature profile of the planetary mantle. From the inferred conditional probabilities we estimate the mineralogy and the temperature profile for the mantle as well as the sulfur weight fraction and the temperature profile for a possible liquid core.
We propose a set of planetary interior models in agreement with the present knowledge of the plan... more We propose a set of planetary interior models in agreement with the present knowledge of the planet Mars. Our spherical, hydrostatic and non-rotating planet is constituted by a crust, parameterized by its mean density, a mantle with variable mineralogy, dependent on pressure and temperature and a partially fluid core composed of iron and sulfur. The crust thickness, the location of the core mantle boundary, the size and state of the inner-core and the concentration of sulfur in the core are adjusted to agree with the total mass and mean moment of inertia.
Despite the tight constraints put by seismology on the elastic properties of the Earth&am... more Despite the tight constraints put by seismology on the elastic properties of the Earth's lower mantle, its mineralogical composition and thermal state remain poorly known because the interpretation of seismic measurements suffers from the trade-off between temperature, iron content, and mineralogical composition. In order to overcome this difficulty, we complement seismic data with electromagnetic induction data. The latter data are
ABSTRACT Among all the planets of the solar system Mercury stands out, because it has a relativel... more ABSTRACT Among all the planets of the solar system Mercury stands out, because it has a relatively high average density compared to its size. To account for this high density, Mercury's core radius is thought to be larger than 34 of its radius. Here, we use recent data about the second-degree gravity field coefficients and measurements about Mercury's rotation – obliquity and 88-day libration amplitude – to obtain constraints on Mercury's interior structure. By combining the gravity field data and the obliquity measurements, the mean moment of inertia of Mercury can be determined. If the coupling between the core and the mantle is neglected then the gravity field data together with the libration amplitude provide an estimate of Mercury's silicate shell moment of inertia. However, since the effect of core–mantle coupling on the 88-day libration amplitude can be about as large as the libration amplitude's uncertainty (Van Hoolst et al., 2012) we use as data the mean moment of inertia and the 88-day libration amplitude to infer knowledge about Mercury's interior structure.
Mars' core is believed to be presently completely liquid. Though the presence of an inner co... more Mars' core is believed to be presently completely liquid. Though the presence of an inner core is not excluded. The existence of an inner core would induce a wobble of the planet which, if excited, could be seen in polar motion, i.e. in the motion of the instantaneous rotation axis in a frame tied to the planet. In this paper, we examine the consequences of an atmospheric excitation of that mode and of the classical Chandler wobble. The presence of an inner core induces also a free inner core nutation and consequently a resonance in the nutations of the planet. These nutations will be observed by the future experiment NEIGE (NEtlander Ionosphere and Geodesy Experiment). We will therefore compute the potential effect of an inner core on these observations.
ABSTRACT A new method is developed to determine the structure of telluric planetary interiors. It... more ABSTRACT A new method is developed to determine the structure of telluric planetary interiors. It is based on the joint inversion of data from in situÿgeophysical experiments and laboratory measurements. We infer conditional probability densities of the parameters governingÿthe internal structure by stochastic inversion. This multi-parameters approach is quite generic and canÿbe applied to any telluric planet. We illustrate it here withÿsimulated data of the future Netlanderÿmission to Mars. The simulated data come from the electromagnetic, geodetic and seismological experiments. This approach is free of any a priori assumption regarding theÿtemperature profile of the planetary mantle. From the inferred conditional probabilities we estimate the mineralogy and the temperature profile for the mantle as well as the sulfur weight fraction and the temperature profile for a possible liquid core.
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Papers by A. Rivoldini