@article{MakuchBrilliantovSremcevicetal.2006, author = {Makuch, Martin and Brilliantov, Nikolai V. and Sremcevic, Miodrag and Spahn, Frank and Krivov, Alexander V.}, title = {Stochastic circumplanetary dynamics of rotating non-spherical dust particles}, series = {Planetary and space science}, volume = {54}, journal = {Planetary and space science}, number = {9-10}, publisher = {Elsevier}, address = {Oxford}, issn = {0032-0633}, doi = {10.1016/j.pss.2006.05.006}, pages = {855 -- 870}, year = {2006}, abstract = {We develop a model of stochastic radiation pressure for rotating non-spherical particles and apply the model to circumplanetary dynamics of dust grains. The stochastic properties of the radiation pressure are related to the ensemble-averaged characteristics of the rotating particles, which are given in terms of the rotational time-correlation function of a grain. We investigate the model analytically and show that an ensemble of particle trajectories demonstrates a diffusion-like behaviour. The analytical results are compared with numerical simulations, performed for the motion of the dusty ejecta from Deimos in orbit around Mars. We find that the theoretical predictions are in a good agreement with the simulation results. The agreement however deteriorates at later time, when the impact of non-linear terms, neglected in the analytic approach, becomes significant. Our results indicate that the stochastic modulation of the radiation pressure can play an important role in the circumplanetary dynamics of dust and may in case of some dusty systems noticeably alter an optical depth. (c) 2006 Elsevier Ltd. All rights reserved.}, language = {en} } @article{KrivovaKrivovMann2000, author = {Krivova, Natalia A. and Krivov, Alexander V. and Mann, Ingrid}, title = {The disk of beta pictoris in the light of polarimetric data}, issn = {0004-637x}, year = {2000}, language = {en} } @article{KruegerKrivovGruen2000, author = {Kr{\"u}ger, Harald and Krivov, Alexander V. and Gr{\"u}n, Eberhard}, title = {A dust cloud around Ganymede Maintained by hypervelocity impacts of interplanetary micrometeoroids}, issn = {0032-0633}, year = {2000}, language = {en} } @article{KrivovMannKrivova2000, author = {Krivov, Alexander V. and Mann, Ingrid and Krivova, Natalia A.}, title = {Size distributions of dust in circumstellar debris discs}, issn = {0935-4956}, year = {2000}, language = {en} } @article{MannKrivovKimura2000, author = {Mann, Ingrid and Krivov, Alexander V. and Kimura, Hiroshi}, title = {Dust cloud near the sun}, year = {2000}, language = {en} } @article{KrivovaKrivovMann2000, author = {Krivova, Natalia A. and Krivov, Alexander V. and Mann, Ingrid}, title = {Size distribution of dust in the disk of Beta Pictoris}, isbn = {1-58381-051-X}, year = {2000}, language = {en} } @article{KrivovBanaszkiewicz2001, author = {Krivov, Alexander V. and Banaszkiewicz, Marek}, title = {Dust Influx to Titan from Hyperion}, isbn = {0-7923-6946-7}, year = {2001}, language = {en} } @article{KrivovBanaszkiewicz2001, author = {Krivov, Alexander V. and Banaszkiewicz, Marek}, title = {Unusual origin, evolution and fate of icy ejecta from Hyperion}, issn = {0032-0633}, year = {2001}, language = {en} } @article{GordonKrivovSchmidtetal.2002, author = {Gordon, M. K. and Krivov, Alexander V. and Schmidt, J{\"u}rgen and Spahn, Frank}, title = {Planetary rings}, year = {2002}, language = {en} } @article{KrivovKruegerGruenetal.2002, author = {Krivov, Alexander V. and Kr{\"u}ger, Harald and Gr{\"u}n, Eberhard and Thiessenhusen, Kai-Uwe and Hamilton, Douglas P.}, title = {A tenuous dust ring of Jupiter formed by escaping ejecta from the Galilean satellites}, issn = {0148-0227}, year = {2002}, language = {en} } @article{GruenKrivov2002, author = {Gr{\"u}n, Eberhard and Krivov, Alexander V.}, title = {Dust astronomy : new venues in interplanetary and interstellar dust research}, isbn = {1-58381-113-3}, year = {2002}, language = {en} } @article{ThiessenhusenKrivovKruegeretal.2002, author = {Thiessenhusen, Kai-Uwe and Krivov, Alexander V. and Kr{\"u}ger, Harald and Gr{\"u}n, Eberhard}, title = {A dust cloud around Pluto and Charon}, issn = {0032-0633}, year = {2002}, language = {en} } @article{KrivovKrivovaSolankietal.2004, author = {Krivov, Alexander V. and Krivova, Natalia A. and Solanki, S. K. and Titov, V. B.}, title = {Towards understanding the beta Pictoris dust stream}, issn = {0004-6361}, year = {2004}, abstract = {The recent radar detection by Baggaley (2000) of a collimated stream of interstellar meteoroids postulated to be sourced at beta Pictoris, a nearby star with a prominent dust disk. presents a challenge to theoreticians. Two mechanisms of possible dust ejection from beta Pic have been proposed: ejection of dust by radiation pressure from comets in eccentric orbits and by gravity of a hypothetical planet in the disk. Here we re-examine observational data and reconsider theoretical scenarios, substantiating them with detailed modeling to test whether they can explain quantitatively and simultaneously the masses, speeds, and fluxes. Our analysis of the stream geometry and kinematics confirms that beta Pic is the most likely source of the stream and suggests that an intensive dust ejection phase took place similar to0.7 Myr ago. Our dynamical simulations show that high ejection speeds retrieved from the observations can be explained by both planetary ejection and radiation pressure mechanisms, providing, however, several important constraints. In the planetary ejection scenario, only a "hot Jupiter"-type planet with a semimajor axis of less than 1 AU can be responsible for the stream, and only if the disk was dynamically "heated" by a more distant massive planet. The radiation pressure scenario also requires the presence of a relatively massive planet at several AU or more, that had heated the cometesimal disk before the ejection occurred. Finally, the dust flux measured at Earth can be brought into reasonable agreement with both scenarios, provided that beta Pic's protoplanetary disk recently passed through an intensive short-lasting (similar to0.1 Myr) clearance stage by nascent giant planets, similar to what took place in the early solar system}, language = {en} } @article{SremcevicKrivovKruegeretal.2005, author = {Sremcevic, Miodrag and Krivov, Alexander V. and Kr{\"u}ger, Harald and Spahn, Frank}, title = {Impact-generated dust clouds around planetary satellites : model versus Galileo}, issn = {0032-0633}, year = {2005}, abstract = {This paper focuses on tenuous dust clouds of Jupiter's Galilean moons Europa, Ganymede and Callisto. In a companion paper (Sremcevic et al., Planet. Space Sci. 51 (2003) 455-471) an analytical model of impact-generated ejecta dust clouds surrounding planetary satellites has been developed. The main aim of the model is to predict the asymmetries in the dust clouds which may arise from the orbital motion of the parent body through a field of impactors. The Galileo dust detector data from flybys at Europa, Ganymede and Callisto are compatible with the model, assuming projectiles to be interplanetary micrometeoroids. The analysis of the data suggests that two interplanetary impactor populations are most likely the source of the measured dust clouds: impactors with isotropically distributed velocities and micrometeoroids in retrograde orbits. Other impactor populations, namely those originating in the Jovian system, or interplanetary projectiles with low orbital eccentricities and inclinations, or interstellar stream particles, can be ruled out by the statistical analysis of the data. The data analysis also suggests that the mean ejecta velocity angle to the normal at the satellite surface is around 30°, which is in agreement with laboratory studies of the hypervelocity impacts. © 2004 Elsevier Ltd. All rights reserved}, language = {en} } @article{KrivovSremcevicSpahn2005, author = {Krivov, Alexander V. and Sremcevic, Miodrag and Spahn, Frank}, title = {Evolution of a Keplerian disk of colliding and fragmenting particles: a kinetic model with application to the Edgeworth-Kuiper belt}, issn = {0019-1035}, year = {2005}, abstract = {We present a kinetic model of a disk of solid particles, orbiting a primary and experiencing inelastic collisions. In distinction to other collisional models that use a 2D (mass-sernimajor axis) binning and perform a separate analysis of the velocity (eccentricity, inclination) evolution, we choose mass and orbital elements as independent variables of a phase space. The distribution function in this space contains full information on the combined mass, spatial, and velocity distributions of particles. A general kinetic equation for the distribution function is derived, valid for any set of orbital elements and for any collisional outcome, specified by a single kernel function. The first implementation of the model utilizes a 3D phase space (mass-semimajor axis-eccentricity) and involves averages over the inclination and all angular elements. We assume collisions to be destructive, simulate them with available material- and size-dependent scaling laws, and include collisional damping. A closed set of kinetic equations for a mass-semimajor axis-eccentricity distribution is written and transformation rules to usual mass and spatial distributions of the disk material are obtained. The kinetic "core" of our approach is generic. It is possible to add inclination as an additional phase space variable, to include cratering collisions and agglomeration, dynamical friction and viscous stirring, gravity of large perturbers, drag forces, and other effects into the model. As a specific application, we address the collisional evolution of the classical population in the Edgeworth-Kuiper belt (EKB). We run the model for different initial disk's masses and radial profiles and different impact strengths of objects. Our results for the size distribution, collisional timescales, and mass loss are in agreement with previous studies. In particular, collisional evolution is found to be most substantial in the inner part of the EKB, where the separation size between the survivors over EKB ' s age and fragments of earlier collisions lies between a few and several tens of km. The size distribution in the EKB is not a single Dohnanyi-type power law, reflecting the size dependence of the critical specific energy in both strength and gravity regimes. The net mass loss rate of an evolved disk is nearly constant and is dominated by disruption of larger objects. Finally, assuming an initially uniform distribution of orbital eccentricities, we show that an evolved disk contains more objects in orbits with intermediate eccentricities than in nearly circular or more eccentric orbits. This property holds for objects of any size and is explained in terms of collisional probabilities. The effect should modulate the eccentricity distribution shaped by dynamical mechanisms, such as resonances and truncation of perihelia by Neptune. (c) 2004 Elsevier Inc. All rights reserved}, language = {en} } @article{MakuchKrivovSpahn2005, author = {Makuch, Martin and Krivov, Alexander V. and Spahn, Frank}, title = {Long-term dynamical evolution of dusty ejecta from Deimos}, issn = {0032-0633}, year = {2005}, abstract = {We re-assess expected properties of the presumed dust belt of Mars formed by impact ejecta from Deimos. Previous studies have shown that dynamics of Deimos particles are dominated by two perturbing forces: radiation pressure (RP) and Mars' oblateness (J2). At the same time, they have demonstrated that lifetimes of particles, especially of grains about ten of micrometers in size, may reach more than 10(4) years. On such timescales, the Poynting-Robertson drag (PR) becomes important. Here we provide a study of the dynamics under the combined action of all three perturbing forces. We show that a PR decay of the semimajor axes leads to an adiabatic decrease of amplitudes and periods of oscillations in orbital inclinations predicted in the framework of the underlying RP+J2 problem. Furthermore, we show that smallest of the long-lived Deimos grains (radius approximate to 5-10 mum) may reach a chaotic regime, resulting in unpredictable and abrupt changes of their dynamics. The particles just above that size (approximate to 10- 15 mum) should be the most abundant in the Deimos torus. Our dynamical analysis, combined with a more accurate study of the particle lifetimes, provides corrections to earlier predictions about the dimensions and geometry of the Deimos torus. In addition to a population, appreciably inclined and shifted towards the Sun, the torus should contain a more contracted, less asymmetric, and less tilted component between the orbits of Phobos and Deimos. (C) 2004 Elsevier Ltd. All rights reserved}, language = {en} }