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  • Articles  (181)
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  • Articles  (181)
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  • 11
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    About Tidal Evolution of Quasi-Periodic Orbits of Satellites (2017)
    Springer
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    Publication Date: 2017-05-13
    Description: Tidal interactions between Planet and its satellites are known to be the main phenomena, which are determining the orbital evolution of the satellites. The modern ansatz in the theory of tidal dissipation in Saturn was developed previously by the international team of scientists from various countries in the field of celestial mechanics. Our applying to the theory of tidal dissipation concerns the investigating of the system of ODE-equations (ordinary differential equations) that govern the orbital evolution of the satellites; such an extremely non-linear system of 2 ordinary differential equations describes the mutual internal dynamics for the eccentricity of the orbit along with involving the semi-major axis of the proper satellite into such a monstrous equations. In our derivation, we have presented the elegant analytical solutions to the system above; so, the motivation of our ansatz is to transform the previously presented system of equations to the convenient form, in which the minimum of numerical calculations are required to obtain the final solutions. Preferably, it should be the analytical solutions; we have presented the solution as a set of quasi - periodic cycles via re-inversing of the proper ultra - elliptical integral. It means a quasi-periodic character of the evolution of the eccentricity, of the semi-major axis for the satellite orbit as well as of the quasi-periodic character of the tidal dissipation in the Planet.
    Print ISSN: 0167-9295
    Electronic ISSN: 1573-0794
    Topics: Geosciences , Physics
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  • 12
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    Coverage of Mars by Probes Slightly Off the Areostationary Orbit (2017)
    Springer
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    Publication Date: 2017-03-19
    Description: This paper aims at investigating the feasibility of gaining complete and continuous coverage of an extended equatorial belt of Mars, under the effects of orbital perturbations. The problem could be solved by considering a minimum number of three probes, which move slightly off the Martian Areostationary Orbit. The proposed configurations allow the achievement of the goal without entailing corrective manoeuvres and presenting only a longitudinal motion with respect to the surface of Mars.
    Print ISSN: 0167-9295
    Electronic ISSN: 1573-0794
    Topics: Geosciences , Physics
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  • 13
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    Observations of Three Stellar Occultations by Comet Hale–Bopp (2017)
    Springer
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    Publication Date: 2017-03-15
    Description: On June 12 1996 UT, three 11–12 R magnitude stars were occulted by comet Hale–Bopp. The passage of these stars through the cometary atmosphere was monitored at the Observatorio do Pico dos Dias (Brazil) using a 0.6 m telescope. We detected an absorption of starlight by the comet dust implying in a drop of \((6\pm 1) \times 10^{-2}\) magnitude of occulted star XPM 152-0898466 at a minimum distance of ( \(4.3 \pm 0.2)\times 10^{4}\)  km from the central condensation. This result, combined with magnitude variations of other stars, suggests the detection of a jet in the coma. From our measurement of extinction, we infer that the opacity of the nucleus surface was \(\tau \sim 3\) . The mean geometric albedo p of dust grains is \((4.5 \pm 0.7) \times 10^{-3}\) . This low albedo may suggest a difference in the grain population associated to coma and jets.
    Print ISSN: 0167-9295
    Electronic ISSN: 1573-0794
    Topics: Geosciences , Physics
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  • 14
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    Shadow Areas Robust Matching Among Image Sequence in Planetary Landing (2016)
    Springer
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    Publication Date: 2016-12-30
    Description: In this paper, an approach for robust matching shadow areas in autonomous visual navigation and planetary landing is proposed. The approach begins with detecting shadow areas, which are extracted by Maximally Stable Extremal Regions (MSER). Then, an affine normalization algorithm is applied to normalize the areas. Thirdly, a descriptor called Multiple Angles-SIFT (MA-SIFT) that coming from SIFT is proposed, the descriptor can extract more features of an area. Finally, for eliminating the influence of outliers, a method of improved RANSAC based on Skinner Operation Condition is proposed to extract inliers. At last, series of experiments are conducted to test the performance of the approach this paper proposed, the results show that the approach can maintain the matching accuracy at a high level even the differences among the images are obvious with no attitude measurements supplied.
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    Electronic ISSN: 1573-0794
    Topics: Geosciences , Physics
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  • 15
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    Forecast of the Comet 46P/Wirtanen Meteor Shower Activity in 2017 and 2019 (2016)
    Springer
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    Publication Date: 2016-12-22
    Description: The article presents the description of possible activity from the comet 46P/Wirtanen meteor shower. The proximity of this comet to the Earth orbit in 1984–2042 increases probabily for the Earth to encounter meteoroid particles released by this comet. For the nearest years two cases of such activity are found—in 2017 and 2019 and their characteristics and circumstances are presented.
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    Electronic ISSN: 1573-0794
    Topics: Geosciences , Physics
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  • 16
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    Relative Effect of Inclinations for Moonlets in the Triple Asteroidal Systems (2016)
    Springer
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    Publication Date: 2016-11-25
    Description: We present the analysis and computational results for the inclination relative effect of moonlets of triple asteroidal systems. Perturbations on moonlets due to the primary’s non-sphericity gravity, the solar gravity, and moonlets’ relative gravity are discussed. The inclination vector for each moonlet follows a periodic elliptical motion; the motion period depends on the moonlet’s semi-major axis and the primary’s J2 perturbations. Perturbation on moonlets from the Solar gravity and moonlet’s relative gravity makes the motion of the x component of the inclination vector of moonlet 1 and the y component of the inclination vector of moonlet 2 to be periodic. The mean motion of x component and the y component of the inclination vector of each moonlet forms an ellipse. However, the instantaneous motion of x component and the y component of the inclination vector may be an elliptical disc due to the coupling effect of perturbation forces. Furthermore, the x component of the inclination vector of moonlet 1 and the y component of the inclination vector of moonlet 2 form a quasi-periodic motion. Numerical calculation of dynamical configurations of two triple asteroidal systems (216) Kleopatra and (153591) 2001 SN263 validates the conclusion.
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    Electronic ISSN: 1573-0794
    Topics: Geosciences , Physics
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  • 17
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    Estimating False Positive Contamination in Crater Annotations from Citizen Science Data (2016)
    Springer
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    Publication Date: 2016-11-20
    Description: Web-based citizen science often involves the classification of image features by large numbers of minimally trained volunteers, such as the identification of lunar impact craters under the Moon Zoo project. Whilst such approaches facilitate the analysis of large image data sets, the inexperience of users and ambiguity in image content can lead to contamination from false positive identifications. We give an approach, using Linear Poisson Models and image template matching, that can quantify levels of false positive contamination in citizen science Moon Zoo crater annotations. Linear Poisson Models are a form of machine learning which supports predictive error modelling and goodness-of-fits, unlike most alternative machine learning methods. The proposed supervised learning system can reduce the variability in crater counts whilst providing predictive error assessments of estimated quantities of remaining true verses false annotations. In an area of research influenced by human subjectivity, the proposed method provides a level of objectivity through the utilisation of image evidence, guided by candidate crater identifications.
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    Electronic ISSN: 1573-0794
    Topics: Geosciences , Physics
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  • 18
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    Lightcurve Analysis, Shapes and Spins of Asteroids Ermolova and Silver from Long-Term Observations (2016)
    Springer
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    Publication Date: 2016-10-25
    Description: We present lightcurves, shapes, and 3D convex spin-axis models for two main-belt asteroids: (3657) Ermolova and (5325) Silver. The photometric data were obtained at the Skalnaté Pleso Observatory (High Tatras, Slovakia) only. The models were obtained with the lightcurve inversion process using combined dense photometric data from the apparitions in 2006, 2010, and 2013 for Ermolova and in 2006, 2010, and 2013 for Silver. The analysis of the resulting data found sidereal periods and possible ecliptic pole solutions (J2000.0). Currently, only 1592 models are known for 907 asteroids. Knowledge of individual asteroid shapes and spin axes is vital for the understanding the Solar System.
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    Electronic ISSN: 1573-0794
    Topics: Geosciences , Physics
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  • 19
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    A Review of Cometary Outbursts at Large Heliocentric Distances (2016)
    Springer
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    Publication Date: 2016-10-22
    Description: The outbursts of comets, sudden large increases in their luminosity, are still very interesting and mysterious signs of activity of this celestial bodies. Most of the cometary outbursts are taking place at heliocentric distances where sublimation of water ice plays an important role in the activity of comets. However, the phenomenon is also observed far away from the Sun (i.e. ≃5–20 au) where the sublimation of water ice is negligible and the activity of comets is dominated by more volatile chemicals. Not only typical comets show ‘cometary-like’ activity but also Centaurs. In addition to the long-term changes in brightness related to heliocentric distances and short-periodic variations connected with the rotation of the nucleus, they also exhibit a random variations in luminosity which are similar to the cometary outbursts. Paper presents an overview of the most likely hypotheses and models which try to explain this phenomenon.
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    Electronic ISSN: 1573-0794
    Topics: Geosciences , Physics
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  • 20
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    The Moon: An Archive of Small Body Migration in the Solar System (2016)
    Springer
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    Publication Date: 2016-10-21
    Description: The Moon is an archive of impact cratering in the Solar System throughout the past 4.5 billion years. It preserves this record better than larger, more complex planets like the Earth, Mars and Venus, which have largely lost their ancient crusts through geological reprocessing and hydrospheric/atmospheric weathering. Identifying the parent bodies of impactors (i.e. asteroid bodies, comets from the Kuiper belt or the Oort Cloud) provides geochemical and chronological constraints for models of Solar System dynamics, helping to better inform our wider understanding of the evolution of the Solar System and the transfer of small bodies between planets. In this review article, we discuss the evidence for populations of impactors delivered to the Moon at different times in the past. We also propose approaches to the identification and characterisation of meteoritic material on the Moon in the context of future lunar exploration efforts.
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    Electronic ISSN: 1573-0794
    Topics: Geosciences , Physics
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