Le Touquet – Paris-Plage, France
Le Touquet – Paris-Plage, France

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Vaubaillon J.,IMCCE | Maquet L.,Paris Observatory | Soja R.,University of Stuttgart
Monthly Notices of the Royal Astronomical Society | Year: 2014

Comet C/2013 A1 will make a very close approach with the planet Mars on 2014 October 19. For this event, we compute the density of cometary dust particles around the Mars Express spacecraft, in order to assess the real risk for space probes. We also estimate the zenithal hourly rate (ZHR) and discuss observational opportunities for the resulting Martian meteor shower. We find, for a surface of 2.7 m2, that the Mars Express spacecraft will experience approximately 10 impacts from particles larger than 100 μm in size. The fluence per square metre is found to be 3.5 during the encounter. The equivalent ZHR is computed to be ZHR ≃ 4.75 × 109 h-1, making this event the strongest meteor storm ever predicted.We call this event a 'meteor hurricane', which we define to be a meteor shower with ZHR exceeding 106 h-1. The event will last approximately 5 h in total, and peak around 20:00 UT (Earth UT time). We call for observations of this unique event by all possible means, but also warn operators of Mars-orbiting spacecraft against the risks of impacts from comet particles larger than 100 μm, with impacts speeds of 57.42 km s-1. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Skokos C.,Aristotle University of Thessaloniki | Skokos C.,University of Cape Town | Gerlach E.,TU Dresden | Bodyfelt J.D.,Massey University | And 2 more authors.
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2014

While symplectic integration methods based on operator splitting are well established in many branches of science, high order methods for Hamiltonian systems that split in more than two parts have not been studied in great detail. Here, we present several high order symplectic integrators for Hamiltonian systems that can be split in exactly three integrable parts. We apply these techniques, as a practical case, for the integration of the disordered, discrete nonlinear Schrödinger equation (DDNLS) and compare their efficiencies. Three part split algorithms provide effective means to numerically study the asymptotic behavior of wave packet spreading in the DDNLS - a hotly debated subject in current scientific literature. © 2014 Elsevier B.V.

Combot T.,IMCCE | Koutschan C.,Johannes Kepler University
Journal of Mathematical Physics | Year: 2012

We prove an integrability criterion of order 3 for a homogeneous potential of degree -1 in the plane. Still, this criterion depends on some integer and it is impossible to apply it directly except for families of potentials whose eigenvalues are bounded. To address this issue, we use holonomic and asymptotic computations with error control of this criterion and apply it to the potential of the form V(r, θ) = r-1h(exp (iθ)) with h ∈ C{double-struck}[z], deg h ≤ 3. We then find all meromorphically integrable potentials of this form. © 2012 American Institute of Physics.

Combot T.,IMCCE
Celestial Mechanics and Dynamical Astronomy | Year: 2012

We prove an integrability criterion and a partial integrability criterion for homogeneous potentials of degree -1 which are invariant by rotation. We then apply it to the proof of the meromorphic non-integrability of the n-body problem with Newtonian interaction in the plane on a surface of equation (H, C) = (H0, C0) with (H0, C0) ≠ (0, 0) where C is the total angular momentum and H the Hamiltonian, in the case where the n masses are equal. Several other cases in the 3-body problem are also proved to be non integrable in the same way, and some examples displaying partial integrability are provided. © 2012 Springer Science+Business Media B.V.

Georgakarakos N.,Abu Dhabi University | Eggl S.,IMCCE
Astrophysical Journal | Year: 2015

The analytical framework presented herein fully describes the motion of coplanar systems consisting of a stellar binary and a planet orbiting both stars on orbital as well as secular timescales. Perturbations of the Runge-Lenz vector are used to derive short-period evolution of the system, while octupole secular theory is applied to describe its long-term behavior. A post-Newtonian correction on the stellar orbit is included. The planetary orbit is initially circular and the theory developed here assumes that the planetary eccentricity remains relatively small (e2 < 0.2). Our model is tested against results from numerical integrations of the full equations of motion and is then applied to investigate the dynamical history of some of the circumbinary planetary systems discovered by NASA's Kepler spacecraft. Our results suggest that the formation history of the systems Kepler-34 and Kepler-413 has most likely been different from that of Kepler-16, Kepler-35, Kepler-38 and Kepler-64, since the observed planetary eccentricities for those systems are not compatible with the assumption of initially circular orbits. © 2015. The American Astronomical Society. All rights reserved.

Combot T.,IMCCE
Celestial Mechanics and Dynamical Astronomy | Year: 2013

We present various properties of algebraic potentials, and then prove that some Morales-Ramis theorems readily apply for such potentials even if they are not in general meromorphic potentials. This allows in particular to precise some non-integrability proofs in Celestial Mechanics, where the mutual distances between the bodies appear in the potential, and thus making this analysis unavoidable. © 2013 Springer Science+Business Media Dordrecht.

Funk B.,University of Vienna | Pilat-Lohinger E.,University of Vienna | Eggl S.,IMCCE
Monthly Notices of the Royal Astronomical Society | Year: 2015

Locating planets in HabitableZones (HZs) around other stars is a growing field in contemporary astronomy. Since a large percentage of all G-M stars in the solar neighbourhood are expected to be part of binary or multiple stellar systems, investigations of whether habitable planets are likely to be discovered in such environments are of prime interest to the scientific community. As current exoplanet statistics predicts that the chances are higher to find new worlds in systems that are already known to have planets, we examine four known extrasolar planetary systems in tight binaries in order to determine their capacity to host additional habitable terrestrial planets. Those systems are Gliese 86, γ Cephei, HD 41004 and HD 196885. In the case of γ Cephei, our results suggest that only the M dwarf companion could host additional potentially habitable worlds. Neither could we identify stable, potentially habitable regions around HD 196885 A. HD 196885 B can be considered a slightly more promising target in the search for Earth-twins. Gliese 86 A turned out to be a very good candidate, assuming that the system's history has not been excessively violent. For HD 41004, we have identified admissible stable orbits for habitable planets, but those strongly depend on the parameters of the system. A more detailed investigation shows that for some initial conditions stable planetary motion is possible in the HZ of HD 41004 A. In spite of the massive companion HD 41004 Bb, we found that HD 41004 B, too, could host additional habitable worlds. © 2015 The Author Published by Oxford University Press on behalf of the Royal Astronomical Society.

We prove a meromorphic integrability condition at order 2 near a homothetic orbit for a meromorphic homogeneous potential of degree -1, which extends the Morales-Ramis conditions of order 1. Conversely, we prove that if this criterion is satisfied, then the Galois group of the second order variational equations is abelian and we compute explicitly the Galois group and Picard-Vessiot extension. Finally, we present an application corollary and some examples. © 2013 IOP Publishing Ltd & London Mathematical Society.

Atreya P.,IMCCE | Atreya P.,Arecibo Observatory | Vaubaillon J.,IMCCE | Colas F.,IMCCE | And 2 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2012

Few high-resolution video cameras have been used for observing meteors, so the orbits obtained have high uncertainty. Precise orbits are necessary so that the meteors can be integrated backwards in time and be identified with their parent body. Also, by comparing these orbits with a theoretical evolution model, the meteors can be associated with a particular dust trail. An electronic shutter system has been developed to enhance the temporal resolution for large CCD sensors. For the first time, an LH100 camera with an electronic shutter system has been tested for observing meteors. This new innovational technique has removed the theoretical upper limit - resulting from slow frame rates - to the size of CCD that can be used for the detection of meteors. Three such cameras will be installed in southern France to create a network for determining the orbits of meteors; this will be called the CAmera for BEtter Resolution NETwork (CABERNET). Here, we present preliminary results from the Geminid test campaign, which made use of this camera. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

Neslusan L.,Slovak Academy of Sciences | Vaubaillon J.,IMCCE | Hajdukova M.,Slovak Academy of Sciences
Astronomy and Astrophysics | Year: 2016

Context. Periodic comets are known to be the parent bodies of meteoroid streams. The stream of a given comet can split into several filaments. These can be observed in the Earth's atmosphere as more than just a single meteor shower. One such comet is C/1917 F1 (Mellish), which associates at least two, possibly four, meteor showers that have been recorded in the meteor databases. In a recent study, the dynamical evolution of the C/1917 F1's theoretical stream was followed by only considering the gravitational perturbations. The properties of individual filaments of this stream, corresponding to the appropriate meteor showers, were not predicted perfectly. Aims. To reach better agreement between theory and observation, we repeatedly model the theoretical stream of C/1917 F1. In the modeling, we also include the Poynting-Robertson drag acting on meteoroids and assume an action of the non-gravitational effects on the parent comet dynamics. If success was achieved, the modeling could become a tool that would enable us to recover the past orbital history of the parent comet. Methods. Considering the nominal orbit, as well as several cloned orbits, of the comet C/1917 F1, we modeled its theoretical streams. The modeling was performed for several past perihelion passages. Each modeled stream consists of 10 000 test particles that are influenced by the Poynting-Robertson drag of various strengths. Results. We achieve a partial improvement in the prediction of the properties of all four meteor showers. The Poynting-Robertson drag helps to improve the match between the theory and observation of three of the four showers. However, when considering the nominal orbit of the parent comet, a perfect match seems to be impossible. A close match in the case of the most problematic shower is achieved using a cloned orbit, but this is not applicable to reality because the simultaneous predictions of the properties of the other three showers fail. © ESO, 2016.

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