National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
YORP effect on asteroids with heterogeneous distribution of surface thermophysical properties
Chrbolková, Kateřina ; Čapek, David (advisor) ; Ďurech, Josef (referee)
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...
Modern numerical models of the YORP effect
Chrbolková, Kateřina ; Čapek, David (advisor) ; Ďurech, Josef (referee)
This thesis deals with the study of an non-gravitational effect called the YORP effect which affects the rotational state of irregularly shaped asteroids. In its first part, there is discussed the very physical nature of this phenomenon and further it demonstrates an effect similar to the YORP: the Yarkovsky effect. Second part analyzes several outstanding numerical models, which describe the YORP effect. It focuses on some aspects that no other models took in account and it also points out what approximations these models make. We have used two different nume- rical models on an asteroid shape of our own and we present it in the last part of this bachelor thesis. At the end of this paper, we compare our outputs with the findings of appropriate models. Our results agree with the cited articles in the majority of cases. We tried to analyze how the YORP effect depends on the chan- ging conductivity of the asteroids and we also found out that better resolution of shapes of asteroids leads to the convergence of the values of the YORP effect.

Interested in being notified about new results for this query?
Subscribe to the RSS feed.