Detailed study of the Yarkovsky effect on asteroids and solar system implications
Author
Spitale, Joseph NicholasIssue Date
2001Keywords
Physics, Astronomy and Astrophysics.Advisor
Greenberg, Richard J.
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The University of Arizona.Rights
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.Abstract
The Yarkovsky effect is a change in a body's orbit caused by its reaction to the momentum carried away by the thermal photons that it emits. This effect may play a key role in the orbital evolution of asteroids and near-Earth objects. To evaluate the Yarkovsky acceleration under a wide range of conditions, I have developed a three-dimensional finite-difference solution to the heat equation. This approach employs neither the linearized boundary conditions, the plane-parallel heat flow approximation, nor the assumption of fast rotation used in earlier approaches (Rubincam, 1998; Vokrouhlickỳ and Farinella, 1998). Thus it can be used to explore a wide range of orbital elements and physical properties that had not been previously accessible. I use the finite-difference approach to compute Yarkovsky perturbations for homogeneous, spherical stony bodies with 1-, 10- and 100-m diameters. For a 1-m scale body rotating with a 5-h period, the semimajor axis can change as much as 1 AU in 1 Myr and the eccentricity can change as much as 0.1 in 1 Myr. These rates are much faster than any found previously because those treatments were not valid for very eccentric orbits. For rotation periods expected to be more typical of such small bodies, these rates would be considerably slower. Nevertheless, there is no data concerning rotation rates for small bodies so these fast rates may be relevant. Yarkovsky drift rates are computed for models of specific near-Earth asteroids, demonstrating that the shape of a body is important in computing its precise Yarkovsky effect. Such calculations may be useful for assessing observable Yarkovsky perturbations and in predicting and mitigating NEA hazards. The approach presented in this dissertation is the only current one with the potential to rigorously treat bodies with arbitrary shapes.Type
textDissertation-Reproduction (electronic)
Degree Name
Ph.D.Degree Level
doctoralDegree Program
Graduate CollegePlanetary Sciences