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1	YORP efekt pro asteroidy s heterogenním rozložením termofyzikálních vlastností povrchu / YORP effect on asteroids with heterogeneous distribution of surface thermophysical properties Chrbolková, Kateřina January 2016 (has links) In this thesis, we study the influence of heterogeneous distribution of optical and thermal properties on asteroid surfaces onto the YORP effect. Modelling of the surface heterogeneities is done in three ways. In the first one, we create an impact crater with higher albedo regolith on a regolith-covered asteroid. In the second way, we suppose presence of higher albedo regolith on steep slopes (slope angle > 35◦ ) and in the third one, we state properties of bare rock (with different thermal parameters) in these areas. Then we evaluate the influence of torques caused by scattered or thermally emitted radiation on 200 asteroids based on different distribution of described parameters by means of statistics. We have found that the presence of heterogeneities caused by landslides on asteroid surfaces does not significantly affect the YORP effect with two exceptions: a slight inclination to decelerate the rotation in the case of landslides uncovering bare rock due to critical rotation and significant preference for deceleration in the configurations with uncovered higher albedo regolith on steep slopes. Our data suggest that the influence of heterogeneous distribution of optical properties caused by landslides on the value of typical acceleration time, so-called doubling time td, is 2 % and it does not exceed 5 % in the case...
2	Radiation Recoil Effects on the Dynamical Evolution of Asteroids Cotto-Figueroa, Desireé January 2013 (has links) No description available. Physics Astrophysics Yarkovsky effect YORP effect aggregate asteroids Near-Earth Asteroids Obliquity distribution Stochastic YORP Self-limiting YORP
3	Design of a Surface Albedo Modification Payload for Near Earth Asteroid (NEA) Mitigation Ge, Shen 2011 August 1900 (has links) The development of the Surface Albedo Treatment System (SATS) onboard a spacecraft mission to the near earth asteroid (NEA) Apophis in 2012 is an innovative concept of deflecting NEAs from possible impact with the Earth through altering the Yarkovsky effect, a non-secular force in the solar system due to uneven surface thermal emission most profoundly affecting small rotating bodies subjected to sunlight. Though this force is small, its magnitude can be dramatic if extended over a period of time and if it uses the close approach of an asteroid near Earth to magnify the perturbation. The payload dispenses colored powder called albedo changing particles (ACPs) onto the surface changing its albedo and indirectly the surface temperature which changes the Yarkovsky effect. This study gives an in-depth description of both computational and experimental parts of the design of this system with primary focus on initial ground test setup. The initial experiments proposed to design the SATS is outlined in detail and justified by the mission criterion of interest as well as modeling the actual dispersal on the surface. albedo Apophis armageddon asteroids deflection NEOs NEAs space mission tribodispenser Yarkovsky effect YORP
4	The Rotation Rate Distribution of Small Near-Earth Asteroids Cotto-Figueroa, Desireé 30 December 2008 (has links) No description available. Astrophysics Near-Earth Asteroids Rotation rate distribution YORP effect Bidirectional reflectance Gaussian random spheres Light curves
5	Numerical N-body approach to binary asteroid formation and evolution Comito, Carlo 03 April 2012 (has links) (PDF) Les astéroïdes binaires ont un rôle d'importance fondamentale dans la détermination de paramètres astéroïdales difficilement mesurables de la Terre, en particulier la masse. En étudiant l'origine des binaires dans le cadre des agrégats gravitationnels, ils servent ainsi comme laboratoires naturels pour la physique des systèmes granulaires à basse gravité, et ils nous donnent des éléments précieux pour la modélisation globale des astéroïdes. Vue la grande diversité existante de caractéristiques des systèmes binaires observés, nombreuses hypothèses ont été postulées pour leur origine (fragmentation catastrophique d'un corps et ré-accumulation sous forme binaire, influences de marée par les planètes, cratérisation, YORP ...). Dans cette thèse nous explorons, grâce à des simulations numériques à N corps, la dynamique d'un agrégat gravitationnel en dehors du régime de stabilité pour un corps simple, en cherchant les configurations les plus favorables à la formation d'un système binaire. Dans une première partie, nous montrons que dans un scénario catastrophique la formation de systèmes binaires est normale, ces-ci bien reproduisant la variété présente dans la population observée. En suite, nous explorons la possibilité d'une déformation progressive d'un agrégat vers un système binaire sous l'action d'une force perturbante agissant lentement jusqu'à la fission éventuelle du corps. Nos résultats proposent des nouveaux regards dans l'étude de la formation des astéroïdes binaires, comme montré par une comparaison avec les observations et la littérature existante. Système solaire astéroïdes formation de satellites méthodes numériques YORP mécanique céleste milieux granulaires
6	Measurement of Adhesion Forces in CM2 Meteorite Materials Zeszut, Zoe 30 August 2017 (has links) No description available. Geology Geological Mineralogy geology geological sciences planetary sciences asteroid asteroids meteorite meteorites cm2 carbonaceous asteroid c type asteroid adhesion cohesion force NASA YORP measurements analog analogue regolith mineral serpentine mineralogy

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