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Daquin J.,Thales Alenia | Deleflie F.,Institute Of Mecanique Celeste Et Of Calcul Des Ephemerides Imcce | Perez J.,ENSTA ParisTech
Acta Astronautica

Abstract We confront stability results over long time scales, considering alternately the averaged and the non-averaged theory to propagate the equations of motion of a celestial body orbiting the vicinity of the (2:1) tesseral resonant surface. This confrontation is performed using Fast Lyapunov Indicator stability maps. The benefit of such maps is threefold: (i) to reveal the whole phase space architecture and the consequences of the resonance overlap when several combinations of tesseral resonant parameters are accounted for, (ii) to perform a stability analysis on a whole phase space region, and (iii) to have a clear view of the possible impacts of the short-periodic effects removed during the averaging procedure. Our detailed numerical investigations conclude that the tesseral chaos is robust to the averaging procedure and the numerical methods used to propagate the equations of motion over such long time scales. © 2015 IAA. Published by Elsevier Ltd. All rights reserved. Source

Segret B.,Laboratoire dEtudes Spatiales et dInstrumentation en Astrophysique LESIA | Vannitsen J.,National Cheng Kung University | Agnan M.,National Cheng Kung University | Porquet A.,Institute Of Mecanique Celeste Et Of Calcul Des Ephemerides Imcce | And 9 more authors.
Proceedings of SPIE - The International Society for Optical Engineering

BIRDY is a 3-Unit CubeSat that is piggy-backed on a host mission to Mars and jettisoned at the beginning of the journey. Then it operates in full autonomy: no assistance, no communication but a beacon signal. The mission profile is a new contribution in Space Weather monitoring and an opportunity to assess the risks in the manned missions to Mars. It counts energetic particles in the maximum range 1 MeV/nucleon to 1 GeV/nucleon. The ground segment prepares a finetuned trajectory to be stored on-board, on the basis of the planed trajectory of the host mission that provides the main delta-V but not the ideal path. It makes the CubeSat compatible with almost all missions going to Mars. During the cruise, the CubeSat relies on an optical planet tracking system to locate itself and on small electrical thrusters to adapt its trajectory and perform the exact flyby at Mars that permits to come back to the Earth. The science data are collected all along the journey and only uploaded once in Mars' vicinity to one of the existing Martian orbiters or rovers, and once at the arrival back to the Earth. More widely than its own scientific mission, BIRDY demonstrates a new way to gather data from distant locations in the solar system. The project is an educational space mission, essentially leaded and designed by students from different educational levels in France and in Taiwan. © 2014 SPIE. Source

Andrade-Ines E.,Institute Of Mecanique Celeste Et Of Calcul Des Ephemerides Imcce | Andrade-Ines E.,University of Sao Paulo | Beauge C.,National University of Cordoba | Michtchenko T.,University of Sao Paulo | Robutel P.,Institute Of Mecanique Celeste Et Of Calcul Des Ephemerides Imcce
Celestial Mechanics and Dynamical Astronomy

We analyse the secular dynamics of planets on S-type coplanar orbits in tight binary systems, based on first- and second-order analytical models, and compare their predictions with full N-body simulations. The perturbation parameter adopted for the development of these models depends on the masses of the stars and on the semimajor axis ratio between the planet and the binary. We show that each model has both advantages and limitations. While the first-order analytical model is algebraically simple and easy to implement, it is only applicable in regions of the parameter space where the perturbations are sufficiently small. The second-order model, although more complex, has a larger range of validity and must be taken into account for dynamical studies of some real exoplanetary systems such as (Formula presented.) Cephei and HD 41004A. However, in some extreme cases, neither of these analytical models yields quantitatively correct results, requiring either higher-order theories or direct numerical simulations. Finally, we determine the limits of applicability of each analytical model in the parameter space of the system, giving an important visual aid to decode which secular theory should be adopted for any given planetary system in a close binary. © 2015, Springer Science+Business Media Dordrecht. Source

Birlan M.,Institute Of Mecanique Celeste Et Of Calcul Des Ephemerides Imcce | Nedelcu D.A.,Astronomical Institute of the Romanian Academy | Descamps P.,Institute Of Mecanique Celeste Et Of Calcul Des Ephemerides Imcce | Berthier J.,Institute Of Mecanique Celeste Et Of Calcul Des Ephemerides Imcce | And 3 more authors.
Monthly Notices of the Royal Astronomical Society

Near-infrared spectroscopy can play a key role in establishing the mineralogical composition of objects and supporting other physical data obtained by complementary observational techniques such as adaptive optics, radar and photometry. The objective of our survey was asteroids that present large variations in their light curves. We report observations for asteroids (854) Frostia, (1333) Cevenola and (3623) Chaplin carried out in the 0.8-2.5μm spectral range using SpeX/Infrared Telescope Facility (IRTF) in LowRes mode. The spectral modelling of these asteroids gives new insights into these peculiar objects in the main belt. (854) Frostia is a V-type asteroid, and its spectral properties are similar to those of basalts. The most probable mineralogical solution Wo8Fs43En49 was calculated for Frostia. (1333) Cevenola was estimated to have an Sq spectral type, in agreement with its membership of the Eunomia family. (3623) Chaplin is an S-type asteroid, in agreement with the taxonomic type of the Koronis family. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS. Source

Frouard J.,Institute Of Mecanique Celeste Et Of Calcul Des Ephemerides Imcce | Frouard J.,Lille University of Science and Technology | Fouchard M.,Institute Of Mecanique Celeste Et Of Calcul Des Ephemerides Imcce | Fouchard M.,Lille University of Science and Technology | And 2 more authors.
Astronomy and Astrophysics

Context. The evection resonance appears to be the outermost region of stability for prograde satellite orbiting a planet, the critical argument of the resonance indeed being found librating in regions surrounded only by chaotic orbits. The dynamics of the resonance itself is thus of great interest for the stability of satellites, but its analysis by means of an analytical model is not straightforward because of the high perturbations acting on the dynamical region of interest. Aims. It is thus important to show the results and the limits inherent in analytical models. We use numerical methods to test the validity of the models and analyze the dynamics of the resonance. Methods. We use an analytical method based on a classical averaged expansion of the disturbing function valid for all eccentricities as well as numerical integrations of the motion and surfaces of section. Results. By comparing analytical and numerical methods, we show that aspects of the true resonant dynamic can be represented by our analytical model in a more accurate way than previous approximations, and with the help of the surfaces of section we present the exact location and dynamics of the resonance. We also show the additional region of libration of the resonance that can be found much closer to the planet due to its oblateness. © ESO, 2010. Source

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