Název:
Thermal Effects in Physics and Dynamics of Small Bodies of the Solar System
Překlad názvu:
Thermal Effects in Physics and Dynamics of Small Bodies of the Solar System
Autoři:
Čapek, David Typ dokumentu: Rigorózní práce
Rok:
2008
Jazyk:
cze
Abstrakt: [cze][eng] Tepelne jevy ve fyzice a dynamice malych teles slunecm soustavy Abstrakt dizertacnf prace David Capek Behem posledni doby se ukazalo, ze tepelne jevy jsou velmi vyznamne v dynamice malych teles slunecni soustavy. Intenzivne studovan byl predevslm jev zvany Jarkovskeho efekt, ktery je schopen dlouhodobe menit velkou poloosn drahy a YORP efekt, jez ovlivnuje rotacni stav telesa. Jarkovskeho a YORP efekt byly drive pocitany s mnoha omezujicimi predpoklady. Napnklad byly uvazovany kulove tvary asteroidu, kruhove drahy, male variace povrchove teploty, rotace okolo hlavni osy tenzoru setrvacnosti, konstantni tepelne parametry a podobne. Proto jsme vyvinnli numericky model pro vypocet Jarkovskeho/YORP jevu, ktery neni omezen temito predpoklady. S timto modelem jsme byli schopni velmi pfesne popsat tvar, drahu, rotaci a tepelne vlastnosti studovaneho telesa. YORP efekt byl studovan na vzorku umele vytvofenych tvaru} ktere odpovidaji aste- roidum hlavniho pasu, a take na tvarech skutecnych asteroidu. Zkoumali jsme zejmena savislost YORP jevu na obliquite a na tepelnych parametrech povrchu. Byla zjistena a diskutovana siroka skala moznosti v)'voje rotacniho stavu asteroidu (Vokrouhlickj'- and Capek, 2002; Capek and Vokrouhlickyj 2004). Pro nektere asteroidy bylo predpovezeno, ze Ize v budoucnosti ocekavat uspesnou...Thermal Effects in Physics and Dynamics of Small Bodies of the Solar System Abstract of the Ph.D. thesis \s David Capek It has been shown, that the thermal effects are very important in the dynamics of small Solar System bodies. A phenomenon which is known as the Yarkovsky effect is able to secularly change the semimajor axis of an orbit, while the YORP effect affects the rotation state of a body. The Yarkovsky effect and the YORP effect were previously calculated with many constraining assumptions like spherical shapes of asteroids, circular orbits, small variations of the surface temperature, principal axis rotation, constant thermal parameters, etc. We developed a sophisticated numerical model of the Yarkovsky/YORP effect without such simplifications. With this model, we have been able to describe the shape, the orbit, the rotation and the thermal behaviour of an asteroid in a very precise way. The YORP effect was studied on a sample of artificially generated shapes, roughly resembling Main Belt asteroids, and also on several shapes of real asteroids. The depen- dence of YORP on the obliquity and the thermal parameters of the surface were studied (Vokrouhlicky and Capek, 2002; Capek and Vokrouhlicky, 2004). A wide variety of pos- sible YORP evolution paths of the spin state was found. The possibility of...