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Your search keyword '"Astronomie et systèmes dynamiques (ASD)"' showing total 753 results
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753 results on '"Astronomie et systèmes dynamiques (ASD)"'

1. Mothership-Cubesat Radioscience for Phobos Geodesy and Autonomous Navigation

Author

Hongru Chen, Nicolas Rambaux, Valéry Lainey, Daniel Hestroffer, Kyushu University, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Planetology and Environments from Ground Astrometry and Space Exploration (PEGASE)

Subjects
Phobos, CubeSats, orbit determination, autonomous navigation, planetary geodesy, radioscience, small bodies, interior structure, General Earth and Planetary Sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; The knowledge of the interior structure (e.g., homogeneous, porous, or fractured) of Martian moons will lead to a better understanding of their formation as well as the early solar system. One approach to inferring the interior structure is via geodetic characteristics, such as gravity field and libration. Geodetic parameters can be derived from radiometric tracking measurements. A feasible mothership-CubeSat mission is proposed in this study with following purposes, (1) performing inter-sat Doppler measurements, (2) improving the understanding of Phobos as well as the dynamic model, (3) securing the mothership as well as the primary mission, and (4) supporting autonomous navigation, given the long distance between the Earth and Mars. This study analyzes budgets of volume, mass, power, deployment Δv, and link, and the Doppler measurement noise of the system, and gives a feasible design for the CubeSat. The accuracy of orbit determination and geodesy is revealed via the Monte-Carlo simulation of estimation considering all uncertainties. Under an ephemeris error of the Mars-Phobos system ranging from 0 to 2 km, the autonomous orbit determination delivers an accuracy ranging from 0.2 m to 21 m and 0.05 mm/s to 0.4 cm/s. The geodesy can return 2nd-degree gravity coefficients at an accuracy of 1, even in the presence of an ephemeris error of 2 km. The achieved covariance matrix of gravity coefficients and libration amplitude indicates an excellent possibility to distinguish families of interior structures.

Published
2022
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2. The Crvenka loess-paleosol sequence: A record of continuous grassland domination in the southern Carpathian Basin during the Late Pleistocene

Author

Thomas Stevens, Michael Zech, Frank Lehmkuhl, Wei Chu, Pál Sümegi, Slobodan B. Marković, Zorica Svirčev, Igor Obreht, Roland Zech, Randall J. Schaetzl, Zoran Peric, Milivoj B. Gavrilov, Björn Buggle, Christian Zeeden, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
010506 paleontology, geography, geography.geographical_feature_category, Pleistocene, Environmental magnetism, Biodiversity, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Paleontology, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Paleosol, Grassland, Deciduous, [SDU]Sciences of the Universe [physics], Loess, Paleoclimatology, Physical geography, Ecology, Evolution, Behavior and Systematics, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract

International audience; In this study, we compare two independent paleoenvironmental proxies for a loess sequence in northern Serbia, in the southern Carpathian Basin: novel n-alkane biomarkers and traditional land snail assemblages. Both are associated with other, more widely used proxy data for loess sections, such as environmental magnetism, grain size, and geochemical indices. Together, these paleoenvironmental proxy records provide evidence for the continued dominance of grasslands during the Late Pleistocene in the Southern Carpathian Basin. It is contrary to other European loess provinces, which are characterized by high diversity of Late Pleistocene environments (ranging from tundra-like to deciduous forest habitats). These findings highlight the southeastern part of Carpathian Basin as an important, but still insufficiently investigated, biogeographical refugium, and biodiversity preservation zone. The reason for this is a mostly stable paleoclimate for much of the Late Pleistocene.

Published
2018
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3. Calibrating Chaos with a Geological Orrery: Precise and accurate measurement of the secular frequencies of the precession of perihelion for the inner planets for 200-222 Ma

Author

Olsen, P. E., Laskar, Jacques, Kent, D. V., Kinney, S., Lepre, C. J., Reynolds, D. J., Rasmussen, C., Mundil, R., Giesler, D., Irmis, R. B., Gehrels, G. E., Geissman, J. W., Sha, J., Parker, W., Whiteside, J. H., Lamont -Doherty Earth Observatory, Palisades, NY, United States, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, EPS, Rutgers University New Brunswick, New Brunswick, NJ, United States, Columbia University, New York, Paleomagnetics Lab, Lamont -Doherty Earth Observatory, Palisades, NY, United States, Raytheon Company, Institute for Fusion Studies, University of Texas, Berkeley Geochronology Ctr, Berkeley, CA, United States, University of Arizona, American Museum of Natural History, Department of Geosciences, Pennsylvania State University, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China, FITA IFAT, and University of Southampton

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; The Geological Orrery is a network of archives of geochronological and orbitally-paced climate proxy data created to address inherent limitations of orbital solutions for planetary orbits beyond 60 Ma due to the chaotic nature of Solar System motion (1). We use results from two NSF-ICDP-funded coring experiments in early Mesozoic continental strata, the Newark Basin Coring Project (2) plus new Hartford basin data (N-H) and the Colorado Plateau Coring Project (3), to precisely and accurately resolve the secular frequencies of the precession of perihelion of the inner planets and Jupiter for the Late Triassic and Early Jurassic epochs, using the lacustrine record of orbital pacing as a geological interferometer. The results are robust, reflecting both an independent U-Pb-based age model based on CPCP zircon U-Pb dates and paleomagnetic polarity correlations and tuning the N-H data to the Venus-Jupiter cycle of 405 ky. MultiTaper Method (MTM) and Frequency Map Analysis (FMA) yield the same results within 0.05% for the 22 Myr-long Triassic-Jurassic window for Mercury, Venus, Earth, and Mars. The overdetermined system of Solar System frequencies are faithfully recorded in the N-H climate proxy data with 16 linear combinations yielding deviations from the measured frequencies (FMA) of only

Published
2018

4. Pallas's formation and internal structure: New insights from VLT/SPHERE

Author

Marsset, Michael, Vernazza, Pierre, Castillo-Rogez, Julie C., Rambaux, Nicolas, Carry, Benoît, Hanus, Josef, Viikinkoski, Matti, Marchis, Franck, Drouard, Alexis, Fetick, Romain, Harissa, Team, Queen's University [Belfast] (QUB), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astéroïdes, comètes, météores et éphémérides (ACME), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Astronomie et systèmes dynamiques (ASD), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), and Henry, Florence

Subjects
[PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Large (D>100km) asteroids are the most direct remnants of the building blocks of planets. (2) Pallas is the third largest asteroid and the parent body of a small collisional family. Its spectral properties indicate a B-type surface, meaning Pallas is most likely linked to carbonaceous chondrite meteorites. Disc-resolved images have revealed a nearly hydrostatic shape overprinted by long-wavelength concavities (Schmidt et al. 2009, Carry et al. 2010). This was interpreted as evidence for an early phase of internal heating subsequent to Pallas's formation, followed by several large impact craters (Schmidt & Castillo-Rogez 2012). Recent estimates of Pallas's density, 2.40±0.25 g/cm3 (Schmidt et al. 2009), 3.40±0.90 g/cm3 (Carry et al. 2010) and 2.72±0.17 g/cm3 (Hanus et al. 2017), are rather inconsistent and prevent from differentiating among the various models proposed for its internal structure (Schmidt & Castillo-Rogez 2012). This currently limits our understanding of the formation and thermal evolution of Pallas. We report new high-angular resolution observations of Pallas collected in the frame of the SPHERE large survey of the asteroid belt (see Talk by P. Vernazza) with the adaptive-optics-fed SPHERE ZIMPOL camera on the VLT. 40 images acquired at 8 epochs provide a full longitudinal coverage of Pallas's southern hemisphere, with Pallas being resolved with ˜120 pixels along its longest axis. The optimal angular resolution of each image was restored with Mistral (Fusco et al. 2002), a myopic deconvolution algorithm optimised for images with sharp boundaries, which allows the identification of many craters and geological features on Pallas. A precise 3D-shape reconstruction was achieved with the ADAM software (Viikinkoski et al. 2015), providing a high precision estimate of Pallas's 3D shape, volume and hence density. Those are used to explore Pallas's early thermal evolution, its subsequent collisional evolution, and its current internal structure and composition. [1] Carry et al. 2010, Icarus, 205, 460 [2] Fusco et al. 2002, SPIE, 4839, 1065 [3] Hanus et al. 2017, A&A, 601, A114 [4] Schmidt et al. 2009, Science, 326, 275 [5] Schmidt & Castillo-Rogez, Icarus, 218, 478 [6] Viikinkoski et al. 2015, A&A, 576, A8

Published
2018

5. Updates from INPOP ephemeris: From fundamental physics tests to lunar interior probe

Author

Viswanathan, Vishnu, Rambaux, Nicolas, Fienga, Agnès, Minazzoli, Olivier, Bernus, Léo, Laskar, Jacques, Gastineau, Mickaël, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Henry, Florence

Subjects
[PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; We present here, our published results obtained with the latest version of the Planetary and Lunar ephemeris - INPOP17a [1]. The lunar part of this solution is fitted to LLR data (1969-2017) with constraints imposed on the lunar gravity field coefficients using estimates derived from the GRAIL mission [2]. The post-fit residuals obtained with INPOP17a reach 1.15cm for the recent and most accurate LLR datasets. We take advantage of this accurate model by performing tests of the Universality of Free Fall (UFF) of the Earth-Moon system in the gravitational field of the Sun, in an attempt to find signatures arising from a differential acceleration of the test bodies. We compare our estimates with other LLR analysis groups and show no violation at the (_3.8 ± 7.1) _ 10_14 [3]. Additional results to be presented include, sensitivity of the UFF violation estimates to various fluid core sizes and the sensitivity of lunar dynamical model parameters to the principal axis PA rotation of the GRAIL solution. The latter as a first attempt to account for incompatibilities found between GRAIL-derived gravity field solutions and LLR estimates [4,5]. Furthermore, new estimates are presented that includes recent 6 months of high accuracy IR LLR data set from Grasse station [6] obtained in 2018.[1] Viswanathan V., Fienga A., Gastineau M., Laskar J., 2017, Notes Scientifiques et Techniques de l'Institut de Mecanique Celeste, Vol. 108[2] Konopliv, A. S. et al. The JPL lunar gravity field to spherical harmonic degree 660 from the GRAIL Primary Mission. J. Geophys. Res. Planets 118, 1415-1434 (2013).[3] Viswanathan, V. et al. The new lunar ephemeris INPOP17a and its application to fundamental physics. Mon. Not. R. Astron. Soc. (2018). doi:10.1093/mnras/sty096[4] Williams, J. G. et al. Lunar interior properties from the GRAIL mission. J. Geophys. Res. Planets 119, 1546-1578 (2014).[5] Viswanathan, V. Improving the dynamical model of the Moon using lunar laser ranging and spacecraft data. (Observatoire de Paris, 2017).[6] Courde, C. et al. Lunar laser ranging in infrared at the Grasse laser station. Astron. Astrophys. 602, A90 (2017).

Published
2018

6. Reconstructing Palaeozoic astronomical frequencies from geological records

Author

Zeeden, Christian, de Vleeschouwer, David, da Silva, Anne-Christine, Laskar, Jacques, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, MARUM-Center for Marine Environmental Sciences, University of Bremen, and University of Liège

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Astronomical tuning is the process of correlating geological records to an astronomical solution, allowing to establish a detailed age model and facilitating the investigation of Earth's climate response to changing boundary conditions in detail. The astronomical solutions that are needed for astronomical tuning consists of reconstructed eccentricity, obliquity and precession through time, and are computed by astronomers. Beyond ca. 12 million years, the phase of obliquity and precession cannot be calculated with confidence. For most of Earth history, the frequencies of obliquity and precession have few constraints. Astronomical models extrapolating recent observations are at least partly problematic because an extrapolation of the present tidal dissipation in the Earth-Moon system would lead to an Earth -Moon collision ca. 1500 Ma ago. Astrochronology has not yet been employed for the quantitative establishment of obliquity and precession frequency, though some qualitative analyses confirm astronomical models for the last ca. 300 Ma. Here, we discuss a novel computation approach for the reconstruction of precession and obliquity frequencies from sedimentary units showing a clear imprint of orbital forcing. We apply this tool to determine the frequency of precession and obliquity, and also the underlying precession constant p, and astronomical g- and s- frequencies, with their uncertainty. This method allows for the reconstruction of recent astronomical properties, confirming its reliability. Using the same method and extrapolating uncertainty for the g- and s- frequencies, we investigate several Devonian datasets and present results for the precession constant as well as precession and obliquity length.

Published
2018

7. Planets in Mean-Motion Resonances and the System Around HD45364

Author

Alexandre C. M. Correia, J.-B. Delisle, Jacques Laskar, Departamento de Física, Universidade de Aveiro (Departamento de Física), Observatoire de Genève, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
Physics, 010504 meteorology & atmospheric sciences, 010308 nuclear & particles physics, Resonance, Astrophysics, Planetary system, 01 natural sciences, Gravitation, Mean motion, Accretion disc, Planet, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Commensurability (astronomy)
Abstract

International audience; In some planetary systems, the orbital periods of two of its members present a commensurability, usually known by mean-motion resonance. These resonances greatly enhance the mutual gravitational influence of the planets. As a consequence, these systems present uncommon behaviors, and their motions need to be studied with specific methods. Some features are unique and allow us a better understanding and characterization of these systems. Moreover, mean-motion resonances are a result of an early migration of the orbits in an accretion disk, so it is possible to derive constraints on their formation. Here we review the dynamics of a pair of resonant planets and explain how their orbits evolve in time. We apply our results to the HD 45365 planetary system.

Published
2018
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8. Radial-velocity fitting challenge. II. First results of the analysis of the data set

Author

X. Dumusque, F. Borsa, M. Damasso, R. F. Díaz, P. C. Gregory, N. C. Hara, A. Hatzes, V. Rajpaul, M. Tuomi, S. Aigrain, G. Anglada-Escudé, A. S. Bonomo, G. Boué, F. Dauvergne, G. Frustagli, P. Giacobbe, R. D. Haywood, H. R. A. Jones, J. Laskar, M. Pinamonti, E. Poretti, M. Rainer, D. Ségransan, A. Sozzetti, S. Udry, Dumusque, X., Borsa, F., Damasso, M., Dã­az, R. F., Gregory, P. C., Hara, N. C., Hatzes, A., Rajpaul, V., Tuomi, M., Aigrain, S., Anglada Escudé, G., Bonomo, A. S., Bouã©, G., Dauvergne, F., Frustagli, G., Giacobbe, Paolo, Haywood, R. D., Jones, H. R. A., Laskar, J., Pinamonti, Matteo, Poretti, E., Rainer, M., Sã©gransan, D., Sozzetti, A., Udry, S., ITA, USA, GBR, CHE, Observatoire de Genève, INAF-Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807, Merate (LC), Italy, INAF-Osservatorio Astrofisico di Torino, via Osservatorio 20, 10025, Pino Torinese, Italy, Department of Physics and Astronomy, University of British Columbia, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Türinger Landessternwarte Tautenburg, Department of Physics, Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Harvard-Smithsonian Center for Astrophysics, and Dipartimento di Fisica, Università di Genova e Sezione INFN

Subjects
Stars: activity, oscillations [stars], Planetary system, Ciencias Físicas, FOS: Physical sciences, Star (graph theory), 01 natural sciences, Signal, purl.org/becyt/ford/1 [https], Methods: data analysis, Planet, Planetary systems, Stars: oscillations, Techniques: radial velocities, Astronomy and Astrophysics, Space and Planetary Science, 0103 physical sciences, data analysis [methods], Limit (mathematics), 010306 general physics, 010303 astronomy & astrophysics, planetary systems, Earth and Planetary Astrophysics (astro-ph.EP), Physics, activity [stars], radial velocitie [Techniques], oscillation [Stars], radial velocities [techniques], purl.org/becyt/ford/1.3 [https], Astronomy and Astrophysic, Computational physics, Radial velocity, Data set, data analysi [Methods], Astronomía, Orbit, 13. Climate action, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Order of magnitude, CIENCIAS NATURALES Y EXACTAS, Astrophysics - Earth and Planetary Astrophysics
Abstract

Radial-velocity (RV) signals induce RV variations an order of magnitude larger than the signal created by the orbit of Earth-twins, thus preventing their detection. The goal of this paper is to compare the efficiency of the different methods used to deal with stellar signals to recover extremely low-mass planets despite. However, because observed RV variations at the m/s precision level or below is a combination of signals induced by unresolved orbiting planets, by the star, and by the instrument, performing such a comparison using real data is extremely challenging. To circumvent this problem, we generated simulated RV measurements including realistic stellar and planetary signals. Different teams analyzed blindly those simulated RV measurements, using their own method to recover planetary signals despite stellar RV signals. By comparing the results obtained by the different teams with the planetary and stellar parameters used to generate the simulated RVs, it is therefore possible to compare the efficiency of these different methods. The most efficient methods to recover planetary signals {take into account the different activity indicators,} use red-noise models to account for stellar RV signals and a Bayesian framework to provide model comparison in a robust statistical approach. Using the most efficient methodology, planets can be found down to K/N= K_pl/RV_rms*sqrt{N_obs}=5 with a threshold of K/N=7.5 at the level of 80-90% recovery rate found for a number of methods. These recovery rates drop dramatically for K/N smaller than this threshold. In addition, for the best teams, no false positives with K/N > 7.5 were detected, while a non-negligible fraction of them appear for smaller K/N. A limit of K/N = 7.5 seems therefore a safe threshold to attest the veracity of planetary signals for RV measurements with similar properties to those of the different RV fitting challenge systems., 36 pages (including 10 pages of appendix), 23 figures, Accepted in A&A

Published
2017

9. La force d'une idée simple : hommage à Claude Shannon à l'occasion du centenaire de sa naissance

Author

Chenciner, Alain, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[MATH]Mathematics [math], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

National audience

Published
2017

10. Tidal constraints on the interior of Venus

Author

Dumoulin, Caroline, Tobie, Gabriel, Verhoeven, Olivier, Rosenblatt, Pascal, Rambaux, Nicolas, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire Royal de Belgique (ORB), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Henry, Florence, Royal Observatory of Belgium [Brussels] (ROB), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Physics::Geophysics
Abstract

International audience; As a prospective study for a future exploration of Venus, we propose to systematically investigate the signature of the internal structure in the gravity field and the rotation state of Venus, through the determination of the moment of inertia and the tidal Love number.We test various mantle compositions, core size and density as well as temperature profiles representative of different scenarios for formation and evolution of Venus. The mantle density rho and seismic vP and vS wavespeeds are computed in a consistent manner from given temperature and composition using the Perple X program. This method computes phase equilibria and uses the thermodynamics of mantle minerals developped by Stixrude and Lithgow-Bertelloni (2011).The viscoelastic deformation of the planet interior under the action of periodic tidal forces are computed following the method of Tobie et al. (2005).For a variety of interior models of Venus, the Love number, k2, and the moment of inertia factor are computed following the method described above. The objective is to determine the sensitivity of these synthetic results to the internal structure. These synthetic data are then used to infer the measurement accuracies required on the time-varying gravitational field and the rotation state (precession rate, nutation and length of day variations) to provide useful constraints on the internal structure.We show that a better determination of k2, together with an estimation of the moment of inertia, the radial displacement, and of the time lag, if possible, will refine our knowledge on the present-day interior of Venus (size of the core, mantle temperature, composition and viscosity). Inferring these quantities from a future ex- ploration mission will provide essential constraints on the formation and evolution scenarios of Venus.

Published
2016
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11. Synthetic spectra of meteors

Author

Guennoun, M., Breton, M.-A., Rambaux, Nicolas, Vaubaillon, Jérémie, Benkhaldoun, Zouhair, Laboratoire de Physique des Hautes Énergies et Astrophysique, Department of Physics, Faculty of Sciences Semlalia (LPHEA), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astéroïdes, comètes, météores et éphémérides (ACME), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Astronomie et systèmes dynamiques (ASD), Roggemans, A., and P.

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Synthetic meteor spectra provide information which help to identify the different types of meteorites resulting from a meteor. They also help anticipate what an instrument might observe in a given range of wavelengths. We developed a program that computes synthetic spectra of meteorites for which we know the chemical formula, in the case of plasma in local equilibrium. Three different examples are presented here.

Published
2016

12. Gravity science investigation of Ceres from Dawn

Author

Park, Ryan S., Konopliv, Alexander S., Bills, Bruce, Castillo-Rogez, Julie C., Asmar, Sami W., Rambaux, Nicolas, Raymond, Carol A., Russell, Christopher T., Zuber, Maria T., Ermakov, Anton, King, Scott, Rayman, Marc, Jet Propulsion Laboratory, California Institute of Technology (JPL), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, University of California, Los Angeles (UCLA), Massachusetts Institute of Technology, Cambridge, MA, United States, and Department of Geoscience, Virginia Tech, Blacksburg, VA, United States

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; The Dawn gravity science investigation utilizes the DSN radiometric tracking of the spacecraft and on-board framing camera images to determine the global shape and gravity field of Ceres. The gravity science data collected during Approach, Survey, and High-Altitude Mapping Orbit phases were processed. Currently, the latest gravity field called CERES08A is available, which is globally accurate to degree and order 5. Combining the gravity and shape data gives the bulk density of 2162.5±8 kg/m3. The low Bouguer gravity at high topography area, or vice versa, indicates that the surface of Ceres is likely compensated and that its interior presents a low-viscosity layer at depth. The degree 2 gravity harmonics show that the rotation of Ceres is very nearly about a principal axis. This consistent with hydrostatic equilibrium at 1% level, and infers a mean moment of inertia of Ceres is 0.36, implying some degree of central condensation. Based on a simple two-layer model of Ceres and assuming carbonaceous chondrites and hydrostatic equilibrium, the core size is expected to be ~280 km with corresponding average thickness of the outer shell of ~190 km.

Published
2016

13. Geodetic data support trapping of ethane in Titan's polar crust

Author

Sotin, Christophe, Rambaux, Nicolas, Jet Propulsion Laboratory, California Institute of Technology (JPL), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Titan's surface is characterized by polar depressions that strongly influence interpretations of the gravity data. This study investigates several geodynamical models that can explain these depressions. For each model, the values of the three moments of inertia are computed numerically by discretizing the interior in spherical coordinates. The study shows that a Pratt model where the polar subsurface is made of ethane clathrates can explain the polar depression, the abrupt jump in altitude at about 60 degrees latitude, and the values of the degree 2 gravity coefficients. This model, proposed by Choukroun and Sotin [1], is based on the stability of ethane clathrate hydrates relative to methane clathrate hydrates. In addition to fitting the geodetic data, it explains the absence of ethane in Titan's atmosphere although ethane is the main product of the photolysis of methane. Other geophysical models based on latitudinal variations in the tidal heating production or in the heat flux at the base of the icy crust do not provide such a good match to the gravity and topographic observations. The ethane-clathrate model predicts that all the ethane produced by photolysis of methane at the present rate during the last billion years could be stored in the polar subsurface. It is consistent with the age of Titan's surface and that of Titan's atmospheric methane inferred from geological and geochemical observations by the Cassini/Huygens mission. The present study also emphasizes the role of mass anomalies on the interpretation of the degree 2 gravity coefficients. It shows that for Titan, a slow rotator, the values of the two equatorial moments of inertia (MoI) are largely affected by the polar depressions whereas the value of polar MoI is not. Therefore, as pointed out by previous calculations [2], calculating the moment of inertia (MoI) factor from the value of J2 could lead to major errors. This is not the case for our preferred Titan's model for which the negative polar mass anomalies are compensated at shallow depth by denser ethane-rich clathrates. This work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. [1] Choukroun M. and Sotin C. (2012) GRL, 39, L04201. [2] Gao and Stevenson (2013) Icarus, 226, 1185-1191.

Published
2016

14. Equilibrium figures of dwarf planets

Author

Rambaux, Nicolas, Chambat, Frédéric, Castillo-Rogez, Julie C., Baguet, Daniel, Henry, Florence, Laboratoire Kastler Brossel (LKB (Jussieu)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Jet Propulsion Laboratory, California Institute of Technology (JPL)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Dwarf planets including transneptunian objects (TNO) and Ceres are >500 km large and display a spheroidal shape. These protoplanets are left over from the formation of the solar System about 4.6 billion years ago and their study could improve our knowledge of the early solar system. They could be formed in-situ or migrated to their current positions as a consequence of large-scale solar system dynamical evolution. Quantifying their internal composition would bring constraints on their accretion environment and migration history. That information may be inferred from studying their global shapes from stellar occultations or thermal infrared imaging. Here we model the equilibrium shapes of isolated dwarf planets under the assumption of hydrostatic equilibrium that forms the basis for interpreting shape data in terms of interior structure. Deviations from hydrostaticity can shed light on the thermal and geophysical history of the bodies. The dwarf planets are generally fast rotators spinning in few hours, so their shape modeling requires numerically integration with Clairaut's equations of rotational equilibrium expanded up to third order in a small parameter m, the geodetic parameter, to reach an accuracy better than a few kilometers depending on the spin velocity and mean density. We also show that the difference between a 500-km radius homogeneous model described by a MacLaurin ellipsoid and a stratified model assuming silicate and ice layers can reach several kilometers in the long and short axes, which could be measurable. This type of modeling will be instrumental in assessing hydrostaticity and thus detecting large non-hydrostatic contributions in the observed shapes.

Published
2016

15. Non-avoided crossings for n-body balanced configurations in R^3 near a central configuration

Author

Chenciner, Alain, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
FOS: Mathematics, 70F10, 70H12, 37J15, 15B57, FOS: Physical sciences, Dynamical Systems (math.DS), Mathematical Physics (math-ph), Mathematics - Dynamical Systems, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Mathematical Physics
Abstract

The balanced configurations are those n-body configurations which admit a relative equilibrium motion in a Euclidean space E of high enough dimension 2p. They are characterized by the commutation of two symmetric endomorphisms of the (n-1)-dimensional Euclidean space of codispositions, the intrinsic inertia endomorphism B which encodes the shape and the Wintner-Conley endomorphism A which encodes the forces. In general, p is the dimension d of the configuration, which is also the rank of B. Lowering to 2(d-1) the dimension of E occurs when the restriction of A to the (invariant) image of B possesses a double eigenvalue. It is shown that, while in the space of all dxd-symmetric endomorphisms, having a double eigenvalue is a condition of codimension 2 (the avoided crossings of physicists), here it becomes of codimension 1 provided some condition (H) is satisfied. As the condition is always satisfied for configurations of the maximal dimension (i.e. if d=n-1), this implies in particular the existence, in the neighborhood of the regular tetrahedron configuration of 4 bodies with no three of the masses equal, of exactly 3 families of balanced configurations which admit relative equilibrium motion in a four dimensional space., 35 pages, 1 diagram, 6 figures Section 1.5.2 is new: it introduces the condition (H) which had been overlooked in the first version

Published
2016
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16. Latitudinal librations of Mercury with a fluid core

Author

Benoît Noyelles, Anne Lemaitre, Nicolas Rambaux, Julien Dufey, Department of Mathematics, University of Namur, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Groupe Astrométrie et Planétologie (GAP)

Subjects
Physics, Solar System, Astronomy and Astrophysics, Geodesy, Orbital period, Celestial mechanics, Physics::Geophysics, Latitude, Astrobiology, Amplitude, Space and Planetary Science, Physics::Space Physics, Libration, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Longitude, Geographic coordinate system, Astrophysics::Galaxy Astrophysics
Abstract

International audience; In the framework of the space missions to Mercury, an accurate model of rotation is needed. Librations around the 3:2 spin-orbit resonance as well as latitudinal librations have to be predicted with the best possible accuracy. In this paper, we use a Hamiltonian analysis and numerical integrations to study the librations of Mercury, both in longitude and latitude. Due to the proximity of the period of the free libration in longitude to the orbital period of Jupiter, the 88-day and 11.86-year contributions dominate Mercury's libration in longitude (with the Hermean parameters chosen). The amplitude of the libration in latitude is much smaller (under 1 arcsec) and should not be detected by the space missions. Nevertheless, we point out that this amplitude could be much larger (up to several tens of arcsec) if the free period related to the libration in latitude approaches the period of the Jupiter-Saturn Great Inequality (883 years). Given the large uncertainties on the planetary parameters, this new resonant forcing on Mercury's libration in latitude should be borne in mind.

Published
2009
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17. Averaging on the motion of a fast revolving body. Application to the stability study of a planetary system

Author

J. Couetdic, Jacques Laskar, François Farago, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
Physics, Stability study, Applied Mathematics, Numerical analysis, Equations of motion, Astronomy and Astrophysics, Parameter space, Planetary system, Computational Mathematics, symbols.namesake, Classical mechanics, Space and Planetary Science, Planet, Modeling and Simulation, symbols, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Hamiltonian (quantum mechanics), Mathematical Physics, Order of magnitude
Abstract

International audience; Exploring the global dynamics of a planetary system involves computing integrations for an entire subset of its parameter space. This becomes time-consuming in presence of a planet close to the central star, and in practice this planet will be very often omitted. We derive for this problem an averaged Hamiltonian and the associated equations of motion that allow us to include the average interaction of the fast planet. We demonstrate the application of these equations in the case of the mu Arae system where the ratio of the two fastest periods exceeds 30. In this case, the effect of the inner planet is limited because the planet's mass is one order of magnitude below the other planetary masses. When the inner planet is massive, considering its averaged interaction with the rest of the system becomes even more crucial.

Published
2009
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18. Gravity tests with INPOP planetary ephemerides

Author

P. Kuchynka, Agnes Fienga, C. Leponcin-Lafitte, Mickael Gastineau, Herve Manche, Jacques Laskar, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC), Systèmes de Référence Temps Espace (SYRTE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Gravity (chemistry), Solar System, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, General Relativity and Quantum Cosmology (gr-qc), Ephemeris, General Relativity and Quantum Cosmology, Acceleration, Pioneer anomaly, Space and Planetary Science, Asteroid, Planet, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

In this paper, we present several gravity tests made in using the last INPOP08 planetary ephemerides. We first propose two methods to estimate the PPN parameter $\beta$ and its correlated value, the Sun J2 and we discuss the correlation between the Sun J2 and the mass of the asteroid ring. We estimate possible advance in the planet perihelia. In the end we show that no constant acceleration larger than 1/4 the Pioneer anomaly can affect the planets of our solar system., Comment: 11 pages. submitted to proceedings of IAU symposium 264 "Relativity in Fundamental Astronomy: Dynamics, Reference Frames and Data analysis"

Published
2009
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19. On the stability of Earth-like planets in multi-planet systems

Author

Áron Süli, Elke Pilat-Lohinger, Philippe Robutel, F. Freistetter, Institut für Astronomie, Universität Wien (IfA), Astronomie et systèmes dynamiques (ASD), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy, Loránd Eötvös University, and Astrophysikalisches Institut und Universitätssternwarte, Friedrich-Schiller-Universität Jena

Subjects
Physics, Solar System, Applied Mathematics, media_common.quotation_subject, Uranus, Orbital resonance, Astronomy, Astronomy and Astrophysics, Computational Mathematics, Jumping-Jupiter scenario, Space and Planetary Science, Planet, Modeling and Simulation, Saturn, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Eccentricity (behavior), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Planetary mass, Mathematical Physics, media_common
Abstract

We present a continuation of our numerical study on planetary systems with similar characteristics to the Solar System. This time we examine the influence of three giant planets on the motion of terrestrial-like planets in the habitable zone (HZ). Using the Jupiter–Saturn–Uranus configuration we create similar fictitious systems by varying Saturn’s semi-major axis from 8 to 11 AU and increasing its mass by factors of 2–30. The analysis of the different systems shows the following interesting results: (i) Using the masses of the Solar System for the three giant planets, our study indicates a maximum eccentricity (max-e) of nearly 0.3 for a test-planet placed at the position of Venus. Such a high eccentricity was already found in our previous study of Jupiter–Saturn systems. Perturbations associated with the secular frequency g 5 are again responsible for this high eccentricity. (ii) An increase of the Saturn-mass causes stronger perturbations around the position of the Earth and in the outer HZ. The latter is certainly due to gravitational interaction between Saturn and Uranus. (iii) The Saturn-mass increased by a factor 5 or higher indicates high eccentricities for a test-planet placed at the position of Mars. So that a crossing of the Earth’ orbit might occur in some cases. Furthermore, we present the maximum eccentricity of a test-planet placed in the Earth’ orbit for all positions (from 8 to 11 AU) and masses (increased up to a factor of 30) of Saturn. It can be seen that already a double-mass Saturn moving in its actual orbit causes an increase of the eccentricity up to 0.2 of a test-planet placed at Earth’s position. A more massive Saturn orbiting the Sun outside the 5:2 mean motion resonance (a S ≥9.7 AU) increases the eccentricity of a test-planet up to 0.4.

Published
2008
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20. The Influence of Giant Planets Near a Mean Motion Resonance on Earth‐like Planets in the Habitable Zone of Sun‐like Stars

Author

Elke Pilat-Lohinger, F. Freistetter, Áron Süli, Philippe Robutel, Institut für Astronomie, Universität Wien (IfA), Department of Astronomy, Loránd Eötvös University, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Astrophysikalisches Institut und Universitätssternwarte, Friedrich-Schiller-Universität Jena

Subjects
Physics, Gas giant, Orbital resonance, Astronomy, Astronomy and Astrophysics, Jupiter, Eccentric Jupiter, Jumping-Jupiter scenario, Space and Planetary Science, Planet, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Planetary mass, Jupiter mass
Abstract

International audience; We present a numerical study of several two-planet systems based on the motions of Jupiter and Saturn, in which the two giant planets move in low eccentric orbits close to a mean motion resonance. It is more likely to find two planets with similar characteristics in a system than a clone of the Jupiter-Saturn pair of our solar system. Therefore, we vary the distance between the two planets and their mass ratio by changing Saturn's semimajor axis from 8 to 11 AU and increasing its mass by factors of 2-40. The different two-planets were analyzed for the interacting perturbations due to the mean motion resonances of the giant planets. We select several mass ratios for the gas giants, for which we study their influence on test bodies (with negligible mass) moving in the habitable zone (HZ) of a Sun-like star. The orbits are calculated for 2×107 yr. In all cases the HZ is dominated by a significant curved band, indicating higher eccentricity, which corresponds to a secular resonance with Jupiter. Interesting results of this study are finding (1) an increase of Venus's eccentricity for the real Jupiter and Saturn masses and the actual semimajor axis of Saturn; (2) an increase of the eccentricity of a test planet at Earth's position when Saturn's mass was increased by a factor of 3 or more; and (3) if the two giant planets are in 2:1 resonance, we observe a strong influence on the outer region of the HZ.

Published
2008
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21. Towards a new model of atmospheric tides: from Venus to super-Earths

Author

Auclair-Desrotour, Pierre, Laskar, Jacques, Mathis, Stéphane, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Tides can strongly affect the evolution of the spin of planets. Super-Earths presenting a solid core and an atmosphere are submitted to both gravitational tides caused by bodies' mutual gravitational interactions and thermal tides resulting from stellar insolation. Thermal tides are particularly important for planets in the habitable zone where they drive the tidal response of the atmosphere (Correia & Laskar 2008). They play a key role for the equilibrium states of the spin, as in the case of Venus (Correia & Laskar 2004) and of exoplanets (e.g. the numerical simulations by Leconte & al. 2015). Given the complex mechanisms involved in thermal tides, analytic models are essential to understand the dependence of the perturbation on the physics on the atmosphere and the tidal frequency. The one proposed in the 60's by Lindzen and Chapman explains well thermal tides in the asymptotic regime of fast rotators but presents a singularity near synchronization. We will present a new analytic approach that generalizes these early works to all regimes of tidal perturbations. This model describes the mechanisms of tidal waves generated in the atmosphere by both gravitational and thermal tides. The tidal torque is computed as a function of the frequency of the forcing and agrees very well with results obtained by direct numerical simulations using General Circulation Models.

Published
2015

22. Hydrodynamical scaling laws to explore the physics of tidal dissipation in star-planet systems

Author

Auclair-Desrotour, Pierre, Mathis, Stéphane, Le Poncin-Laffite, Christophe, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Boisse, I., Demangeon, O., Bouchy, F., Arnold, and L.

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Fluid celestial bodies can be strongly affected by tidal perturbations, which drive the evolution of close planetary systems over long timescales. While the tidal response of solid bodies varies smoothly with the tidal frequency, fluid bodies present a highly frequency-resonant tidal dissipation resulting from the complex hydrodynamical response. In these bodies, tides have the form of a combination of inertial waves restored by the Coriolis acceleration and gravity waves in the case of stably stratified layers, which are restored by the Archimedean force. Because of processes such as viscous friction and thermal diffusion, the energy given by the tidal forcing is dissipated. This directly impact the architecture of planetary systems. In this study, we detail a local analytical model which makes us able to characterize the internal dissipation of fluid bodies as functions of identified control parameters such as the inertial, Brunt-Väisälä and tidal frequencies, and the Ekman and Prandtl numbers.

Published
2015

23. Tidal formation of Hot Jupiters in binary star systems

Author

Bataille, M., Libert, Anne-Sophie, Correia, Alexandre C. M., Department of Physics, I3N, University of Aveiro, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; More than 150 Hot Jupiters with orbital periods less than 10 days have been detected. Their in-situ formation is physically unlikely. We need therefore to understand the migration of these planets from high distance (several AUs). Three main models are currently extensively studied: disk-planet interactions (e.g. [3]), planet-planet scattering (e.g. [4]) and Kozai migration (e.g. [2]). Here we focus on this last mechanism, and aim to understand which dynamical effects are the most active in the accumulation of planetary companions with low orbital periods in binary star systems. To do so, we investigate the secular evolution of Hot Jupiters in binary star systems. Our goal is to study analytically the 3-day pile-up observed in their orbital period. Our framework is the hierarchical three-body problem, with the effects of tides, stellar oblateness, and general relativity. Both the orbital evolution and the spin evolution are considered. Using the averaged equations of motion in a vectorial formalism of [1], we have performed # 100000 numerical simulations of well diversified three-body systems, reproducing and generalizing the numerical results of [2]. Based on a thorough analysis of the initial and final configurations of the systems, we have identified different categories of secular evolutions present in the simulations, and proposed for each one a simplified set of equations reproducing the evolution. Statistics about spin-orbit misalignements and mutual inclinations between the orbital planes of the Hot Jupiter and the star companion are also provided. Finally, we show that the extent of the 3 day pile-up is very dependent on the initial parameters of the simulations.

Published
2015

24. Coorbital motion in the co-planar RTBP: family of Quasi-satellite periodic orbits

Author

Pousse, Alexandre, Robutel, Philippe, Vienne, Alain, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Planetology and Environments from Ground Astrometry and Space Exploration (PEGASE)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; In the framework of the Restricted Three-body Problem (RTBP), we consider a primary whose mass is equal to one, a secondary on circular or eccentric motion with a mass # and a massless third body. The three bodies are in coplanar motion and in co-orbital resonance. We actually know three classes of regular coorbital motions: in rotating frame with the secondary, the tadpole orbits (TP) librate around Lagrangian equilibria L4 or L5; the horseshoe orbits (HS) encompass the three equilibrium points L3, L4 and L5; the quasi-satellite orbits (QS) are remote retrograde satellite around the secondary, but outside of its Hill sphere. Contrarily to TP orbits which emerge from a fixed point in rotating frame, QS orbits emanate from a oneparameter family of periodic orbits, denoted family-f by Henon (1969). In the averaged problem, this family can be understood as a family of fixed points. However, the eccentricity of these orbits can reach high values. Consequently a development in eccentricity will not be efficient. Using the method developed by Nesvorny et al. (2002) which is valid for every values of eccentricity, we study the QS periodic orbits family with a numerical averaging. In the circular case, I will present the validity domain of the average approximation and a particular orbit. Then, I will highlight an unexpected result for very high eccentricity on families of periodic orbits that originate from L3, L4 and L5. Finally, I will sketch out an analytic method adapted to QS motion and exhibit associated results in the eccentric case.

Published
2015

25. On the detectability of quasi-circular co-orbital planets. Application to the radial velocity technique

Author

Leleu, Adrien, Robutel, Philippe, Correia, Alexandre C. M., Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Departamento de Fisica, Universidade de Lisboa

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Several celestial bodies in co-orbital configurations exist in the Solar System. However, co-orbital exoplanets are yet to be discovered. This lack may result from a degeneracy between the signal induced by coorbital planets and other orbital configurations. Here we determine a criterion for the detectability of quasicircular co-orbital planets and develop a demodulation method to bring out their signature from the observational data. We show that the precision required to identify a pair of co-orbital planets depends only on the libration amplitude and on the planet's mass ratio. We apply our method to synthetic radial velocity data, and show that for tadpole orbits we are able to determine the inclination of the system to the line-of-sight. Our method is also valid for planets detected through the transits or astrometry techniques.

Published
2015

26. On the rotation of co-orbital bodies

Author

Robutel, Philippe, Leleu, Adrien, Correia, Alexandre C. M., Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Departamento de Física, Universidade de Aveiro (Departamento de Física)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; The rotation of asymmetric bodies in eccentric Keplerian orbits may be chaotic. As it is the case for Hyperion[1], this phenomenon is due to the overlapping of spin-orbit resonances. For a Keplerian motion with small eccentricity, the only relevant spin-orbit resonance is the synchronous one (when the orbital frequency is equal to the rotation frequency as it is the case for the Moon). As a consequence, the rotation is generally regular. Here we are interested in the rotation of a body whose orbital motion is perturbed by a third one. The situation in which the rotator and the perturbing body are in co-orbital resonance (1:1 orbital resonance) is particularly interesting. We demonstrate that, even when the eccentricities of the trajectories are small, stable non-synchronous rotation is possible for a wide range of mass ratios and body shapes [2]. We further show that the rotation becomes chaotic when the natural rotational libration frequency, due to the axial asymmetry, is of the same order of magnitude than the orbital libration frequency inside the co-orbital resonance. When the co-orbital bodies evolve on elliptic orbits with significant eccentricities, case in which non-synchronous spin-orbit resonances are possible on Keplerian orbits, a new kind of spin-orbit resonance appears.

Published
2015

27. Frequency analysis and representation of slowly diffusing solutions

Author

Fu, Yanning, Laskar, Jacques, Purple Mountain Observatory, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Given numerically a KAM solution of a Hamiltonian system, the frequency analysis algorithm NAFF allows to recover its significant periodic terms, and as thus to provide a compact quasi-periodic representation with high precision. In astronomical practice, however, it is often necessary to take into consideration frequency drifts of chaotic and/or dissipative nature. The aim of the present report is to develop a numerical algorithm of representing slowly diffusing solutions of a perturbed integrable Hamiltonian system. By simple analytical considerations, we first argue that it is possible to recover exactly a single varying frequency. Then, a function basis involving time-dependent fundamental frequencies is formulated in a semi-analytical way. Finally, starting from a numerical solution, a recursive algorithm is designed to numerically decompose the solution on the significant elements of the function basis. Simple examples show that this algorithm can be used to give compact representations of different types of slowly diffusing solutions. As practically useful examples, such representations spanning [-35Myr,5Myr] are obtained for the eccentricity and the inclination of the Earth, which are known to be chaotic.

Published
2015

28. Appendix: Final Update of the IAU Division A Commission 4 Working Group on Standardizing Access to Ephemerides and File Format Specification

Author

James L. Hilton, Dmitry Pavlov, Agnes Fienga, Patrick T. Wallace, Vladimir I. Skripnichenko, William M. Folkner, Mickael Gastineau, Charles H. Acton, E. V. Pitjeva, Steven A. Bell, Jean-Eudes Arlot, N. Capitaine, United States Naval Observatory (USNO), Jet Propulsion Laboratory, California Institute of Technology (JPL), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Planetology and Environments from Ground Astrometry and Space Exploration (PEGASE), HM Nautical Almanac Office, Systèmes de Référence Temps Espace (SYRTE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Rotation de la Terre et géodésie spatiale, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Institute of Applied Astronomy, and RAL Space, Rutherford Appleton Laboratory

Subjects
Space and Planetary Science, Computer science, business.industry, Group (periodic table), Astronomy and Astrophysics, Commission, Division (mathematics), Software engineering, business, File format, Ephemeris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Web site
Abstract

The IAU Commission 4 Working Group on Standardizing Access to Ephemerides recommends the use of the Spacecraft and Planet Kernel (SPK) format to provide a uniform format for the position ephemerides of planets and other natural solar system bodies, and the use of the Planetary Constants Kernel (PCK) for the orientation of these bodies. These formats are used by the SPICE system, developed by the Navigation and Ancillary Information Facility of NASA's Jet Propulsion Laboratory. The working group's final report is currently undergoing final preparations for publication. A long version of this report will be available at the IAU Commission 4: Ephemerides (or its successor) web site. This long version will contain a full description of that portion of the SPK and PCK formats required to duplicate these file types for this application.

Published
2015
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29. Recent developments in INPOP planetary ephemerides

Author

Fienga, Agnes, Viswanathan, Vishnu, Laskar, Jacques, Manche, Hervé, Gastineau, Mickael, Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; 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 beyond the Neptune orbit will also be presented.

Published
2015

30. Historical Reflections on the Work of Commission 4

Author

John A. Bangert, George H. Kaplan, William Thuillot, Marina Lukashova, Sean E. Urban, William M. Folkner, Mitsuru Soma, Steven A. Bell, Catherine Y. Hohenkerk, Agnes Fienga, E. V. Pitjeva, José M. Ferrándiz, Jean-Eudes Arlot, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Planetology and Environments from Ground Astrometry and Space Exploration (PEGASE)

Subjects
010504 meteorology & atmospheric sciences, media_common.quotation_subject, Astronomy and Astrophysics, Commission, 01 natural sciences, Management, Work (electrical), Space and Planetary Science, Political science, Service (economics), 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, media_common
Abstract

International audience; Commission 4 was among the first set of commissions formed within the IAU at its founding in 1919. (Commissions were originally called ``Standing Committees.'') During its 96 years of service to the IAU and astronomical community in general, the commission has been fortunate to have been led by many distinguished scientists - see the list of presidents below.

Published
2015
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31. Utilizing the Lunar Laser Ranging datasets alongside the radioscience data from the Lunar Reconnaissance Orbiter to improve the dynamical model of the Moon

Author

Viswanathan, Vishnu, Fienga, Agnès, Laskar, Jacques, Manche, Hervé, Torre, Jean-Marie, Courde, Clément, Exertier, Pierre, Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; 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 derived from this process on combining with the high precision Lunar Laser Ranging (LLR) datasets which are spread over 40 years, facilitates an improved dynamical modeling of the Moon. In addition, the possible advantages that could be exploited by the LLR experiments when operated with lasers in the IR wavelength are analyzed.

Published
2015

32. IAU Working Group for Numerical Standards of Fundamental Astronomy (NSFA): Past Efforts and Future Endeavors

Author

Luzum, Brian, Capitaine, Nicole, Fienga, Agnès, Folkner, William M., Fukushima, Toshio, Heinkelmann, Robert, Hilton, James L., Hohenkerk, Catherine, Petit, Gérard, Pitjeva, Elena V., Soffel, Michael, Wallace, Patrick, US Naval Observatory, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Rotation de la Terre et géodésie spatiale, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Jet Propulsion Laboratory, California Institute of Technology (JPL), National Astronomical Observatory of Japan, European Southern Observatory (ESO), HM Nautical Almanac Office, Bureau International des Poids et Mesures (BIPM), Institute of Applied Astronomy RAS, Jakokoski Observatory, University of Helsinki, and STFC Rutherford Appleton Laboratory

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; In 2006, the International Astronomical Union (IAU) General Assembly (GA) established the Working Group (WG) for Numerical Standards of Fundamental Astronomy (NSFA). The NSFA WG Current Best Estimates (CBEs) were adopted at the 2009 IAU GA in Resolution B2 as the IAU (2009) System of Astronomical Constants. The IAU 2012 Resolution on the re-definition of the au was proposed by the NSFA WG. Since then, the WG has concentrated on establishing the process for maintaining the CBEs in an effort to provide a service for the IAU. The NSFA web presence documents both the IAU (2009) System of Astronomical Constants and the CBEs. All old pages of the CBEs are archived in order to document history of the CBEs. The CBE policy documents the procedures established for proposal, discussion, and voting for the adoption of new CBEs. The talk reviews the efforts of the WG and provides insight into future efforts.

Published
2015

33. Parallel sparse multivariate polynomial division

Author

Jacques Laskar, Mickael Gastineau, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Jean-Guillaume Dumas, Erich L. Kaltofen, and Clément Pernet

Subjects
Multi-core processor, Theoretical computer science, Shared memory, Computer science, Scalability, Scalable algorithms, Multivariate polynomials, Binary heap, Sparse approximation, Parallel computing, Division (mathematics), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We present a scalable algorithm for dividing two sparse multivariate polynomials represented in a distributed format on shared memory multicore computers. The scalability on the large number of cores is ensured by the lack of synchronizations during the main parallel step. The merge and sorting operations are based on binary heap or tree data structures.

Published
2015
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34. Librations et structure interne de Titan et Mimas

Author

Richard, Andy, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2015

35. Dynamique et observations des systèmes planétaires multiples

Author

Laskar, Jacques, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

National audience

Published
2015

36. Campus spatial Curiesat à l'UPMC. Projets nanosatellites étudiants

Author

Rambaux, Nicolas, Galayko, Dimitri, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

National audience

Published
2015

37. An approach for estimating the planetary influence on Solar

Author

Baidolda, Farida, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2015

38. Coorbital resonance dynamics : an introduction to Quasi-satellite motion

Author

Pousse, Alexandre, Robutel, Philippe, Vienne, Alain, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Planetology and Environments from Ground Astrometry and Space Exploration (PEGASE)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2015

39. On the origin of stellar spin-orbit angle in extrasolar systems

Author

Boué, Gwenaël, Laskar, Jacques, Fabrycky, Daniel C., Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2015

40. INPOP : un problème dans les échelles de temps ?

Author

Manche, Hervé, Laskar, Jacques, Fienga, Agnès, Gastineau, Mickaël, Bouquillon, Sébastien, Francou, Gérard, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

National audience

Published
2015

41. Table ronde éphémérides

Author

Imcce, ., Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astéroïdes, comètes, météores et éphémérides (ACME), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Astronomie et systèmes dynamiques (ASD), and Planetology and Environments from Ground Astrometry and Space Exploration (PEGASE)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

National audience

Published
2015

42. Enceladus’ long-period physical librations

Author

Giese, B., Rambaux, Nicolas, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
Enceladus, Physics::Space Physics, Planetengeodäsie, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Physics::Geophysics, Physical librations
Abstract

International audience; The predicted long-period librational response of Saturn's moon Enceladus[1] proceeds on the assumption that the spin pole is inertially fixed. Actually,the spin pole is expected to occupy a Cassini state [2] where it tracks the motion of the precessing orbit pole [3]. Here we show that this would result in additional long - period libration frequencies with appreciable amplitudes.

Published
2015

43. Scaling laws to quantify tidal dissipation in star-planet systems

Author

Auclair-Desrotour, Pierre, Mathis, Stéphane, Le Poncin-Laffite, Christophe, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Martins, F., Boissier, S., Buat, V., Cambrésy, L., Petit, and P.

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), FOS: Physical sciences, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

Planetary systems evolve over secular time scales. One of the key mechanisms that drive this evolution is tidal dissipation. Submitted to tides, stellar and planetary fluid layers do not behave like rocky ones. Indeed, they are the place of resonant gravito-inertial waves. Therefore, tidal dissipation in fluid bodies strongly depends on the excitation frequency while this dependence is smooth in solid ones. Thus, the impact of the internal structure of celestial bodies must be taken into account when studying tidal dynamics. The purpose of this work is to present a local model of tidal gravito-inertial waves allowing us to quantify analytically the internal dissipation due to viscous friction and thermal diffusion, and to study the properties of the resonant frequency spectrum of the dissipated energy. We derive from this model scaling laws characterizing tidal dissipation as a function of fluid parameters (rotation, stratification, diffusivities) and discuss them in the context of star-planet systems., Comment: 5 pages, 3 figures, SF2A conference

Published
2015
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44. Quasi-Periodic Almost-Collision Orbits in the Spatial Three-Body Problem

Author

Lei Zhao, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
Applied Mathematics, General Mathematics, 010102 general mathematics, Mathematical analysis, Zero (complex analysis), Dynamical Systems (math.DS), Collision, Three-body problem, 01 natural sciences, Measure (mathematics), Lower limit, Planar, 37N05, 70F15, 70F16, 0103 physical sciences, FOS: Mathematics, Limit (mathematics), Mathematics - Dynamical Systems, ddc:510, 0101 mathematics, Quasi periodic, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Mathematics
Abstract

In a system of particles, quasi-periodic almost-collision orbits are collisionless orbits along which two bodies become arbitrarily close to each other -- the lower limit of their distance is zero but the upper limit is strictly positive -- and which are quasi-periodic in a regularized system up to a change of time. The existence of such orbits was shown in the restricted planar circular three-body problem by A. Chenciner and J. Llibre, and later, in the planar three-body problem by J. F\'ejoz. In the spatial three-body problem, the existence of a set of positive measure of such orbits was predicted by C. Marchal. In this article, we present a proof of this fact., Comment: 25 pages, 2 figures

Published
2015
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45. Two examples of resurgence

Author

Olivé, Carme, Sauzin, D., Martínez-Seara Alonso, M. Teresa|||0000-0001-8421-8717, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Groupe Astrométrie et Planétologie (GAP), Universitat Politècnica de Catalunya. Departament de Matemàtica Aplicada I, and Universitat Politècnica de Catalunya. EGSA - Equacions Diferencials, Geometria, Sistemes Dinàmics i de Control, i Aplicacions

Subjects
Differential equations, Equacions diferencials funcionals, Hyperbolic singular point, 37 Dynamical systems and ergodic theory::37G Local and nonlocal bifurcation theory [Classificació AMS], Homoclinic trajectories, Equacions diferencials ordinàries, Resurgence, Divergent series, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Asymptotic calculus, Splitting of separatrices, Equacions en diferències, 34 Ordinary differential equations::34M Differential equations in the complex domain [Classificació AMS]
Abstract

This paper gives an account of two articles which illustrate the use of Resurgence theory for estimating the diference between two complex invariant manifolds associated with the area-preserving H?enon map for the first one, and with a Hamiltonian system which stems from the rapidly forced pendulum for the second one.

Published
2005
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46. Generalizing the classical fixed-centres problem in a non-Hamiltonian way

Author

A Albouy, T J Stuchi, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Instituto de Física, Universidade Federal do Rio Grande do Sul

Subjects
Integrable system, Generalization, Mathematical analysis, General Physics and Astronomy, Statistical and Nonlinear Physics, Numerical integration, Mathematical Operators, Gravitation, symbols.namesake, Bounded function, Euler's formula, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Hamiltonian (quantum mechanics), Mathematical Physics, Mathematics, Mathematical physics
Abstract

International audience; The problem of two gravitational (or Coulombian) fixed centres is a classical integrable problem, stated and integrated by Euler in 1760. The integrability is due to the unexpected first integral G. We introduce some straightforward generalizations of the problem that still have the generalization of G as a first integral, but do not possess the energy integral. We present some numerical integrations showing the main features of their dynamics. In the domain of bounded orbits the behaviour of these a priori non-Hamiltonian systems is very similar to the behaviour of usual near-integrable systems.

Published
2004
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47. Hg-Mask Coronagraph

Author

P. Bourget, P. Assus, R. Vieira Martins, François Colas, C. H. Veiga, Observatorio Nacional - Rio de Janeiro, Brazil, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Aime, C., Soummer, and R.

Subjects
Physics, business.industry, Dynamic range, General Engineering, Astronomy and Astrophysics, Occultation, law.invention, Telescope, Cardinal point, Optics, Apodization, Space and Planetary Science, Observatory, law, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Adaptive optics, business, Coronagraph
Abstract

In order to optimize the occulting process of a Lyot coronagraph and to provide a high dynamic range imaging, a new kind of occulting disk has been developed at the National Observatory of Rio de Janeiro. A mercury (Hg) drop glued onto an optical window by molecular cohesion and compressed by a pellicle film is used as the occulting disk. The minimum of the superficial tension potential function provides an optical precision (lambda/100) of the toric free surface of the mercury. This process provides a size control for the adaptation to the seeing conditions and to the apparent diameter of a resolved object, and in the case of adaptive optics, to the Airy diameter fraction needed. The occultation is a three dimensional process near the focal plane on the toric free surface that provides an apodization of the occultation. The Hg-Mask coronagraph has been projected for astrometric observations of faint satellites near to Jovian planets and works since 2000 at the 1.6 m telescope of the Pico dos Dias Observatory (OPD - Brazil).

Published
2004
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48. Estimation of zonal errors in star catalogs using CCD observations of ICRF sources

Author

A. H. Andrei, A. Fienga, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Observatório do Valongo, Universidade Federal do Rio de Janeiro

Subjects
Physics, Homogeneity (statistics), Astronomy, Astronomy and Astrophysics, Astrophysics, Astrometry, Star (graph theory), Declination, Stars, Space and Planetary Science, Distortion, Magnitude (astronomy), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Right ascension
Abstract

International audience; 38 optical counterparts of ICRF sources were observed and positions were deduced using USNO A2.0 stars and stars extracted from the preliminary version of the GSC II catalog, named GSC2.2. These positions were compared to the ICRF positions, and to other published positions of the same optical counterparts. A significant distortion of the USNO A2.0 catalog is revealed for stars fainter than the 11th magnitude and with declinations from 0 to 20 deg. On the other hand, the preliminary version of the GSC II catalog shows a very good external accuracy and a good homogeneity in right ascension and declination for the observed zones.

Published
2002
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49. Accuracy limit of modern ephemerides imposed by the uncertainties in asteroid masses

Author

A. Fienga, E. M. Standish, Jet Propulsion Laboratory, California Institute of Technology (JPL), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
Physics, Astronomy, Astronomy and Astrophysics, Astrometry, Fundamental ephemeris, Ephemeris, Celestial mechanics, Photometry (astronomy), [SDU]Sciences of the Universe [physics], Space and Planetary Science, Asteroid, Very-long-baseline interferometry, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Right ascension
Abstract

International audience; Accuracy limits in the ephemerides of the four inner planets, imposed by uncertainties in the masses of the asteroids, are investigated and illustrated. We consider present-day knowledge of the asteroid masses (determined by the IRAS survey, direct dynamical determinations, ground-based photometry, occultations, etc.), and we model the distribution of those masses. This distribution is then used in a Monte Carlo study, repeatedly adjusting the ephemerides to fit the observational data, each time using a different, but equally-likely, set of asteroid masses. The differences in the resulting ephemerides are shown. If the full inherent weighting of the highly accurate ranging data is used, stretching over more than two decades, the orbits become distorted in right ascension and declination - as much as 5 kilometers or more. If the ranging is de-weighted to a level equivalent to the other two coordinates (1-2 mas, determined by VLBI), then a reasonable ephemeris results, showing uncertainties of 2-3 kilometers. It is also possible to produce an ephemeris which will extrapolate a year or so into the future at the sub-kilometer level (as is often required for spacecraft navigation). This can be done by fully-weighting only the recent observational data. However, the ephemeris farther from the fitting interval is seen to deteriorate rapidly.

Published
2002
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50. Les petits corps du système solaire : astéroïdes, comètes, météores

Author

Carry, Benoît, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Groupe Astrométrie et Planétologie (GAP)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

National audience

Published
2014

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