FIENGA , Agnès

In this work, we have begun the first adjustment of the analytical theories of the planets built at the IMC-BDL, VSOP. We had gathered together several types of observations, reduced and homogenized them. There are very different types of data : old and recent transit observations spread on a period of more than 2 centuries (1750-1997),...

We describe here how planetary ephemerides are built in the framework of General Relativity and how they can be used to test alternative theories. We focus on the definition of the reference frame (space and time) in which the planetary ephemeris is described, the equations of motion that govern the orbits of solar system bodies and light rays....

We use MCMC to sample the posterior distribution of the mass of the graviton -- assumed here to be manifest through a Yukawa suppression of the Newtonian potential -- by using INPOP planetary ephemerides. The main technical difficulty is the lack of analytical formulation for the forward problem and the cost in term of computation time for its...

Perturbations in the Main Belt Asteroids (MBAs) are the major obstacle for achieving increased prediction accuracy in planetary ephemerides, especially for Mars, as the large quantities of asteroids make ephemeris calculations computationally difficult and complex. In this study, a multiple-ring model of the main asteroid belt is proposed...

Computing the tidal deformations of Mars, we explored various Mars spherically symmetric internal structures with different types of interface between the mantle and the liquid core. By assessing their compatibility with a diverse set of geophysical observations we show that despite the very short periods of excitation, tidal deformation is...

Computing the tidal deformations of Mars, we explored various spherical internal structures and different types of interface between the mantle and the liquid core. We demonstrate that the geodetic records associated with thermal constraints are very sensitive to the presence of a 2-layered interface on the top of the liquid core. This...

Context: We are testing strong equivalence principle with planetary ephemerides in the frame of the Brans-Dicke class of scalar tensor theories. Aims: In this work, we apply our recently proposed Bayesian methodology on the Brans-Dicke case, with an emphasis on the issue of the strong equivalence principle. Methods: We compare the posterior...

We present here the new version of the INPOP planetary ephemerides based on an update of the observational data sets as well as new results in term of asteroid masses and constraints obtained for General relativity parameters PPN beta, gamma, J2 and the secular variations of G. New constraints about the hypothetical existence of a super-Earth...

In this work, we investigated Bayesian methodologies for constraining in the Solar System a Yukawa suppression of the Newtonian potential -- which we interpret as the effect of a non-null graviton mass -- by considering its impact on planetary orbits. Complementary to the previous results obtained with INPOP planetary ephemerides, we consider...

The tidal deformations of a planet are often considered as markers of its inner structure. In this work, we use the tide excitations induced by the Sun on Venus for deciphering the nature of its internal layers. In using a Monte Carlo Random Exploration of the space of parameters describing the thickness, density and viscosity of 4 or 5 layer...

Seismological models from Apollo missions provided the first records of the Moon inner structure with a decrease in seismic wave velocities at the core–mantle boundary1,2,3. The resolution of these records prevents a strict detection of a putative lunar solid inner core and the impact of the lunar mantle overturn in the lowest part of the Moon...

Aims. We are testing the Brans–Dicke class of scalar tensor theories with planetary ephemerides.Methods. In this work, we apply our recently proposed Bayesian methodology to the Brans–Dicke case, with an emphasis on the issue of the strong equivalence principle (SEP).Results. We use an MCMC approach coupled to full, consistent planetary...

We used the INPOP19a planetary ephemerides to perform the orbital adjustment of 14099 asteroids based on Gaia-DR2 observations and compare for 23 of them the resulting orbits to radar data. As Gaia-DR2 has been processed using the planetary ephemeris INPOP10e, the primary goal of this paper is to confirm the portability of the data when using...

Current knowledge of Mercury orbit is mainly brought by the direct radar ranging obtained from the 60s to 1998 and five Mercury flybys made by Mariner 10 in the 70s, and MESSENGER made in 2008 and 2009. On March 18, 2011, MESSENGER became the first spacecraft orbiting Mercury. The radioscience observations acquired during the orbital phase of...

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When a light scalar field with gravitational strength interacts with matter, the weak equivalence principle is in general violated, leading for instance to a violation of the universality of free fall. This has been known and tested for a while. However, recent developments [Minazzoli & Hees, PRD 2016] showed that a novel manifestation of the...

Modern technological developments have pushed the accuracy of astrometric measurements in the visible band down to the micro-arcsec level. This allows to test theories of gravity in the weak field limit to unprecedented level, with possible consequences spanning from the validity of fundamental physics principles, to tests of theories...

In this poster we elaborate the use of raw navigation data (range and Doppler observations) from the Lunar Reconnaissance Orbiter (LRO) available on the Planetary Data System (PDS), in order to study the orbit of this probe using the orbit determination software (GINS) developed by the French space agency (CNES). The constraints that are...

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The Moon is the most well-known extraterrestrial planetary body thanks to observations from ground-based, space-borne instruments and lunar surface missions. Data from Lunar Laser Ranging (LLR), magnetic, gravity, surface observations and seismic Apollo ground stations help us to quantify the deformation undergone by the Moon due to body tides....

LLR in IR (1064nm) gives an improvement in the temporal and spatial distribution of observations. Estimates of the lunar core using IR data will be presented.